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starknaked25
08-25-2013, 12:13 AM
I just lost my third BN pleco today and I have no idea why they keep dying. I have a 30g planted tank, the tank mates are 5 regular/green tiger barbs, 3 cherry barbs and a rainbow shark, I also added two nerite snales after the second died. The plants in the tank are two, approx 12in, amazon swords, some dwarf hairgrass (only in one corner not a carpet), an anubious nana, Java fern and two cardinal plants, I think they are cardinals they are as new as my last pleco was. There is a piece of driftwood in there leaning on the back of the tank so it creates shade, there is also a fake hollow log and a small cave type ornament. My light stays on for about 12 hrs per day, mainly because I turn it on at about 7:30 before work then I get home around 5:30 or 6 so I keep it on a little so I can see them.

My first BN lasted about a week or two, he didn't seem to do much, the second lasted about six weeks, it was very active but I went out of town and when I got home it had vanished, I never found any trace of him. The last one lasted a week, he stayed under the driftwood most of the time but started to come out a little and stayed behind the heater. After the first I started feeding vegetables, mainly zucchini which he loved, I also gave him some brussel sprouts. The third never found the zucchini, I also tried wafers with this one but I don't think he found those either even though I put them right by him, but the barbs liked them.

All the other fish have been doing just fine and when I have had my water tested it has been fine, they said the levels were good or maybe once something was just in an acceptable range. The first two plecos were from petsmart, the third was from a local non-chain store. I have done weekly water changes of at least 10% and I do 25% monthly. Is there anything I am doing wrong, what can I do different?

Spardas
08-25-2013, 01:12 AM
I'm going to go with starvation and/or water issues.

Do you know the exact parameters other than the LFS saying "it's fine"? Do you know the pH/hardness of your tank? 12 hours of light is also excessive. You can set a timer so that it'll turn on in the afternoon and go into the night time before you sleep but not to exceed 8 hours.

How big are those tiger barbs? How did you prepare the veggies for them?

starknaked25
08-25-2013, 03:02 AM
For the water test the PH was neutral, once I think it was slightly off but that was early on, ammonia and nitrites were zero, not sure the measurements on the hardness but once it was slightly on the hard side but within an acceptable range. I have not had issues with my other fish so I figured it wouldnt be the water.

The tiger barbs are no more than about 1 1/2 in. The most aggressive in the tank is the rainbow shark but I have only seen that towards the barbs when they get fed and the come around the bottom, he would swim right by the pleco and not bother it at all and I have never seen any other fish bother them either.

I boil the veggies for 1-2 mine then freeze them for later use. I then thaw them out and put a veggie clip on them or weigh them down to keep them on the bottom. For this latest pleco it could have starved but I never saw it on any of the food I gave it, it would just hide all the time.

I thought the light could be an issue since it is on so long but I have also seen that you shouldn't turn it off and on throughout the day so that is why I leave it on after I feed them in the morning.

Spardas
08-25-2013, 03:58 AM
How big is the driftwood? Do you see the pleco chew on it at all?

What is your nitrate at?

As for the lights, just set a timer for the afternoon going until you sleep. This way, you can see your tank at night after work. 8 hours is enough. Are you having any algae issues?

talldutchie
08-25-2013, 06:35 AM
12 hours of light won't bother fish. We don't have a water quality picture.

nitrates?
ph?
hardness?

With only 2 plants is there any shelter at all for this fish?

DoubleDutch
08-25-2013, 08:25 AM
As spardas says : add some "soft" wood they can eat of and realize they go crazy for bloodworms, high protein tablets as well. They are omnivores and not only herbivores. Mine will be the first ar the Cory-pellets for that. Though on cumcumber as well !!!

Byron
08-25-2013, 04:05 PM
I concur with what has been mentioned, and it may be a combination of these issues. Bristlenose are in the Ancistrus genus, though the exact species of the common "bristlenose" is not known, and many suggest it is a hybrid, which is why it is so tolerant of parameters provided they are not excessively hard. It is omnivorous though primarily vegetarian, but meaty as well as veggie based foods are necessary. Algae would be wise especially at first, as this fish is primarily an algae grazer. We don't know the feeding conditions prior to its arrival in your tank, and it may have been nearly starved and beyond hope, like many otos are. It needs wood, you have that.

Ancistrus species are basically nocturnal, so minimum light (have floating plants) will help to bring it out more, and I agree to lessen the duration.

The other thing that stands out to me is the shark. These are often intolerant of other substrate dwellers, and even if you have not noticed any aggression, it may still occur when you are not there, or at night. I acknowledge this is general, and some individual fish may react fine, but it is a possible. And any stress added to the introduction stress can often be one level of stress too much, especially if the fish is already weakened.

Byron.

SueD
08-25-2013, 04:05 PM
I would suggest 50% water changes every week, along with cleaning the substrate - at least half the tank at a time. A well-fed pleco is going to poop a lot. I have 4 BN's in different tanks and this is one of my favorite fish. Sorry you are having such trouble with yours.

starknaked25
08-25-2013, 11:42 PM
I checked my water to be sure of the condition. The PH is 7.5, my tap water is the same. My ammonia is .25ppm, nitrites 0ppm, and nitrates were at 40ppm before a 25% water change, down to about 10ppm after the change. Alkalinity is about 140ppm which looks like 7.84 when converted to dKH. I have looked at two sites for pH level for a BN and one said 6.5-7.4 the other 7-8 so either I am just out of the range or right in the middle. The temp is about 77 degrees.

The drift wood is roughly in a triangle shape and about 9in on each side. It leans against the back wall so the underside is all in shade. Most other shade is from the two tall Amazon Swords and then two ornaments, one is a hollow log about 12in long the other is a rock structure with a hollow center that is about 7in by 8in. There is not a ton of shade, my hope was the Java Fern would grow to shade a bit of the back of the tank.

I have thought about cutting down the feedings on my other fish to one a day and cutting down light time. The less feeding should drop that ammonia to 0 and the light should help him come out. However as my tank is in my dining room there is usually ambient light from elsewhere so it will not be incredibly that dark, but it won’t be direct overhead light. When I do a water change I always use a siphon and clean the rocks, but with plants I try to stick away from their base so I am not pulling up their roots. I used to get a bit of a green film over the rocks in the front of my tank and a bit on the glass, I would vacuum the rocks and wipe down the glass and it would take about a week to come back. Over that last few weeks the amount has dropped quite a bit and there is only a little that shows up each week. The front of the drift wood is still covered in green though.

I am very new at keeping an aquarium so thanks for all the help.

Byron
08-26-2013, 12:38 AM
I checked my water to be sure of the condition. The PH is 7.5, my tap water is the same. My ammonia is .25ppm, nitrites 0ppm, and nitrates were at 40ppm before a 25% water change, down to about 10ppm after the change. Alkalinity is about 140ppm which looks like 7.84 when converted to dKH. I have looked at two sites for pH level for a BN and one said 6.5-7.4 the other 7-8 so either I am just out of the range or right in the middle. The temp is about 77 degrees.

The drift wood is roughly in a triangle shape and about 9in on each side. It leans against the back wall so the underside is all in shade. Most other shade is from the two tall Amazon Swords and then two ornaments, one is a hollow log about 12in long the other is a rock structure with a hollow center that is about 7in by 8in. There is not a ton of shade, my hope was the Java Fern would grow to shade a bit of the back of the tank.

I have thought about cutting down the feedings on my other fish to one a day and cutting down light time. The less feeding should drop that ammonia to 0 and the light should help him come out. However as my tank is in my dining room there is usually ambient light from elsewhere so it will not be incredibly that dark, but it won’t be direct overhead light. When I do a water change I always use a siphon and clean the rocks, but with plants I try to stick away from their base so I am not pulling up their roots. I used to get a bit of a green film over the rocks in the front of my tank and a bit on the glass, I would vacuum the rocks and wipe down the glass and it would take about a week to come back. Over that last few weeks the amount has dropped quite a bit and there is only a little that shows up each week. The front of the drift wood is still covered in green though.

I am very new at keeping an aquarium so thanks for all the help.

I am seeing a bit more now, with this information. This is why we all ask for the data; many factors are interconnected.

Your pH is fine. Ranges for pH are approximate and not exact, something to aim for. You're fine. The ammonia and nitrate are not, I'll come back to these.

The green film/algae is/was due to the light, so reducing the duration will help. Other than this, you are fine with the light, don't worry about more shade, that sounds OK.

Next issue though is the ammonia and high nitrates; ammonia should never be above zero, and nitrates at 40ppm is to me very high. I know, you will read some people think this is fine, but I can assure you it is not; many sources are now recommending 20ppm as absolute maximum, and 10ppm is better. And lowering to 10ppm after the water change tells us the nitrate is within the tank, not in the tap water, so that is easier to solve. This also had something to do with that algae, as the nitrates indicate organics, and that is food for algae if the plants can't use it first.

SudD mentioned this in her post, and I agree. More regular water changes to keep the nitrates down are needed. Pleco are waste factories, as some call them, but you can manage it with weekly partial water changes, vacuuming the substrate where it is open. Change half the tank volume every week, use a good conditioner. This will help all the fish.

I guess the pleco is dead, so before getting another I would suggest you decide on the pleco or the shark.

Byron.

Strider199
08-26-2013, 12:59 AM
Ammonia and pleco's don't go together. Tank need to be cycled with 0ppm ammonia as was already said. That shark may also be a problem as Byron stated. Unless the pleco is really comfortable and has enough hiding places, your shark will drive the pleco nuts. The two are after the same food and both think the tank is theirs.
Do you have another tank to put the shark into while the pleco becomes comfortable? Make sure there are enough hiding places for a pleco (add pvc pipe if your not sure), and when you feed your pleco keep an eye on what happens. The shark may be guarding the food.
But most important is that ammonia. Take care of that now with water changes before it effects your other stock.

starknaked25
08-26-2013, 01:50 AM
Byron you mentioned using a good quality water conditioned, what would you recommend? I currently treat my tap water with Kordon NovAqua Plus water conditioner and aquarium salt.

I have seen the shark be protective of veggies but only towards the barbs, he will chase them away a lot. However I have seen a previous pleco sitting on zucchuni and the shark would swim right by and not bother it. He may bug the pleco at other times but I have just never seen it. I am thinking of gettiing a rock to put in the back and raise it slightly off the rocks so the pleco will be the only thing that can get under it or adding something else like the pvc.

I will definately do more frequent changes, feed the other fish a little less and check the ammonia to make sure it drops.

Spardas
08-26-2013, 02:08 AM
Ah, the salt.....

Please don't perform water changes with salt.

starknaked25
08-26-2013, 02:23 AM
What is wrong with salt, should I not use it at all?

Spardas
08-26-2013, 02:40 AM
Aquarium salt should really be used during treatment. There's absolutely no need to add it. How much are you adding into the tank every water change?

Plecos don't appreciate salt either. It'll tolerate it to a degree but it won't thrive in it. Your main problems are ammonia, high nitrate, and constant addition of salt into the tank......

starknaked25
08-26-2013, 03:13 AM
The recommended dose is 1/2 a rounded teaspoon per gallon. I do just under a half of a teaspoon or a little less per gallon, so under the recommended dose.

talldutchie
08-26-2013, 05:06 AM
But you're not keeping brackish fish, or are you? What is salt supposed to accomplish?
And are you aware that your tank is too small for a rainbow shark long term? Especially combined with another bottom dweller.

William
08-26-2013, 10:41 AM
What is wrong with salt, should I not use it at all?

Salt will only help mask problems they will not solve any. The salt can help prevent disease outbrakes that would otherwise happen when water quality is low. However it will do nothing to improve water quality and you fish will still have poor water conditions that have a negative affect on its health, cause stress and reduce the life span of the fish.

IE If you keep a clean aquarium with good water quality the salt will do nothing. If you have poor water quality it will mask some symptoms but you fish will still suffer/be negatively affected.

Salt should never be used with scaleless fish such as catfish (pleco is one) or loaches. These fishes have a very tolerance for salt. You should not be using it at all in a tank with these type of fishes.

I recommend that you stop using it all together. It will stand in your way to becoming a good fish keeper and will slow down the learning curv by making you think things are well when they are infact not okay.

Occassional use to treat ich outbreakes is another story but I would still choose other solutions in tanks with scaleless fish.

Byron
08-26-2013, 03:59 PM
Others have correctly said it, but as you asked I will just add my agreement that you should never use salt in a freshwater aquarium except when it is the "best" treatment, and rarely will it be better. For the reason why, I will cut and paste an article I wrote on salt and what it does to fish. I have known aquarist who literally burned the skin off pleco with salt at "normal" dose. The Kordon NovAqua is fine, I used that conditioner for years; I've switched to another, NutraFin AquaPlus, only because I can get it for less money, and being retired on a fixed income this is a concern. Here's the story on salt:

Numbers in square brackets indicate a citation from the applicable reference works listed at the end.

Many fish stores, and other “sources of wisdom” about fishkeeping, will recommend salt as a general "tonic" for freshwater tropical fish. The usual suggested dosage of salt is something like a teaspoon per 5 gallons. As David A. Lass points out, there is not much therapeutic benefit at those dosages. “Salt serves more to assuage the hobbyist's need to ‘do something’ for their tropical fish,” he writes. [8] There is absolutely no need to add salt to freshwater aquaria except as a specific treatment, and even here the sensitivity of certain fish species must be kept in mind. Fish health expert Dr Peter Burgess says he certainly doesn't advocate salt for permanent use: "Unless the species has a natural requirement for salt, then we should not add salt to an aquarium (or pond).” [1]

As the scientific data presented in this summary article indicates, adding salt to a freshwater aquarium on a regular basis will, at best, do nothing of any value at all. But at worst, it will stress salt-intolerant fish, making them more vulnerable to disease and less likely to live a healthy and normal lifespan. To understand why, we need to understand what salt does in water, and how fish are affected. But before this, we must clarify just what we mean by “salt.”

Sodium chloride

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge) [Wikipedia, definition of “Salt (chemistry)”]. There are mineral salts for most minerals. But for the purpose of this article, we are dealing solely with common salt—what we know as table salt, or rock salt, or aquarium salt. This salt is a mineral that is composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of ionic salts. It is essential for animal life in small quantities, but it is harmful to animals and plants in excess. Marine salt has other minerals in it too, but it is still “salt” for the purpose of this discussion.

Salt is an irritant, which causes the fish to secrete more mucus particularly in the gills where osmoregulation is occurring. And if salt is not predissolved carefully, it can give fish bad burns; this is especially true for scaleless fish, such as loaches, many catfish and some types of eels. [9]

Salt makes the water denser than the same water without salt. The aquarium contains water. The bodies of fish and plant leaves also contain water, just as we do—humans are approximately 70% water. The water in the aquarium and the water in the fish/plant are separated by a semi-permeable layer which is the cell. Water can and continually does pass through this cell; fish do not “drink” because they don’t have to in order to take in water. When either body of water is denser, the other less-dense body of water will pass through the membrane to equalize the water on both sides. The fish must control this process through what is termed osmoregulation.

Freshwater Fish Physiology

Salt definitely interferes with the osmotic regulation of fish and plants. It should be left alone; nature regulated that part itself, by creating freshwater, brackish and saltwater fish. The vast majority of freshwater fish live in waters having no measurable salinity, and this has been crucial in the evolution of their physiology. Fresh water fish differ physiologically from salt water fish in several respects: their gills must be able to diffuse dissolved gasses while keeping the salts in the body fluids inside; their scales reduce water diffusion through the skin; and they also have well developed kidneys to reclaim salts from body fluids before excretion.

Freshwater fish have physiological mechanisms that permit them to concentrate salts within their bodies in a salt-deficient environment; marine fish, on the other hand, excrete excess salts in a hypertonic environment. Fish that live in both environments retain both mechanisms. Freshwater fish concentrate salts to compensate for their low salinity environment. They produce very dilute but copious urine—up to a third of their body weight each day—to rid themselves of excess water, while conducting active uptake of ions at the gills. [2]

The kidneys of freshwater fish have two functions: osmoregulation [discussed below] and hematopoiesis, which is the formation of blood celular components. Each fish species is adapted to the range of salts in its habitat water, and the kidneys function well within that range. The kidneys have to work harder whenever the salt content of the water in which the fish is living is greater than that of the fish’s preference, i.e., the natural habitat. The closer the water is to the species’ requirements, the easier it will be for the fish to maintain proper osmotic levels. One of the myths about the “benefit” of regular addition of salt is that it allegedly maintains an osmoregulatory balance; in point of fact, regular use of salt has the exact opposite effect and can cause bloating due to an osmotic imbalance. [3]

Osmoregulation is the technical term for the physiological mechanism fish use to control the amount of salt and water in their bodily fluids. As the name suggests, it's based on osmosis. Water is constantly passing through the cells of freshwater fish by osmosis in an attempt to equate the water inside the fish with the water in the aquarium. Freshwater fish regularly excrete this water through respiration and urination; the average fish will urinate 30% of its body mass every day. The more salt in the aquarium water, the greater the strain on the fish's kidneys, which in turn adds to the fish's stress in attempting to maintain their internal stability.

And salinity affects the amount of energy the fish must spend to maintain the physiological equilibrium—the complex chain of internal chemical reactions that keep the pH of the fish’s blood steady, its tissues fed, and the immune system functioning. When salinity increases beyond what the fish is designed by nature to handle, the fish must work harder and use more energy just to “keep going.” Laura Muha [4] likens this to driving a car up a steep hill—it takes more energy (gas) to maintain the same speed as driving on level ground, and it causes more “wear and tear.” This increased energy output is wearing down the fish, and the fish is not able to expend this crucial energy on other important functions. The growth rate is affected, a shorter lifespan will usually result, and there will be increased risk of various health problems along the way.

Fish and plants from mineral-poor waters do not appreciate being kept in slightly saline water conditions. Many of the most popular fish today, like cardinal tetra and rasbora, come from soft water habitats. Short term exposure to low salt concentrations across a few days or a couple of weeks may not do them major harm, but constant use of salt in their aquaria could cause problems. [5] In Weitzman et al. (1996), the authors mention that 100 ppm of salt is the maximum that can be tolerated by most characins, and some species show considerable stress leading to death at a level of 60 ppm. [6] To put this in perspective, 100 ppm is approximately equal to 0.38 gram of salt per gallon of water. One level teaspoon holds approximately six grams of salt, so just 1 teaspoon of salt in 16 gallons of water will cause stress, and in some species lead to death.

Another problem is that salt increases the total dissolved solids [TDS] in the water. An aquarium treated with one teaspoon of salt per gallon of water will have an established dose of 2400 ppm. Add to this the TDS occurring from calcium and magnesium salts [these make water “hard”], water conditioners and other additives, and you can end up with over 3000 ppm of TDS. [10] This is intolerable for most fish; even the very hard water in the African rift lakes does not contain more than 600 ppm TDS. And for fish from naturally soft and acidic water environments, this is very dangerous, for nowhere in nature does acidic water exist with a level of TDS anywhere near this. And the deviation from normal osmotic pressure that this creates is very harmful to all fish.

Keeping the tank salty all the time will not help with disease resistance in freshwater fish; in fact, it will actually increase the fishes’ susceptibility to disease and parasites by keeping the fish somewhat stressed all the time, and this weakens the immune system. And at the low level of salt generally recommended for these so-called benefits, there will be no benefit that cannot be achieved solely with regular water changes using a good conditioner.

Some concluding thoughts...

Using salt to increase water hardness

Although plain aquarium/tonic salt (sodium chloride) is sometimes suggested as a good way to increase hardness and improve buffering, it in fact provides very little of either. Marine salt mix, on the other hand, will raise the pH and carbonate hardness quite significantly. But it also raises the salinity, something most freshwater fish do not appreciate. If you live in a soft water area and want to keep hard water fish, using marine salt mix is not really a viable option. Rift Valley cichlids, in particular, seem to be peculiarly sensitive to salt, and elevated salinity levels have been identified as one factor responsible for the dropsy-like disease known as Malawi Bloat (Andrews, et al. 1988). [7]

Fish lore also has it that salt is good for use with mollies, other livebearers and goldfish. David Lass [8] notes that the vast majority of livebearers, including mollies of all types and colors, and sailfins, come from the Far East. They have been raised for generations in water that is moderately hard, and of neutral pH. These tropical fish are very far removed from the wild mollies that came from brackish water. All of the sailfin and lyretail mollies, balloon bellies, blacks, reds, and dalmations do fine without salt. The same with goldfish. The main confusion is that tropical fish need alkalinity. Salt is just one part of alkalinity.

Although NaCl is not composed of any truly "hard" ions, it does raise the total dissolved solids in the water, and these contribute to raise general hardness. This is not well tolerated by a number of fish, especially true softwater fish from places like the Amazon River basin, where there are very few electrolytes of any kind in the water. Salt can have an unpredictable effect on softwater fish, since there are no bodies of water in Nature which are naturally saline (high in NaCl) while being very low in "true" hardness ion concentration (calcium, magnesium, potassium, etc.). [9]

Salt and Plants: When salt is added to the aquarium water, the water inside the plant cells is less dense so it escapes through the cells. The result is that the plant literally dries out, and will wilt. I've so far been unable to find a measurement of how much salt will be detrimental to plants; all authorities I have found do note that some species are more sensitive than others, and all recommend no salt in planted aquaria.

Domestic water softeners: Domestic water softeners do not produce soft water in the sense that aquarists mean. What domestic water softeners do is remove the temporary hardness (such as carbonates) that potentially furs up pipes and heaters by replacing it with permanent hardness (such as chlorides) that does not. While you can pass this softened water through a reverse-osmosis filter to remove the permanent hardness as well, until you have done so, you shouldn't consider the softened water as being suitable for soft water fish.

In fact, aquarists are divided on whether the resulting softened water is safe for keeping fish at all. The odd balance of minerals in softened water is not typical of any of the environments from which tropical fish are collected. While the chloride levels are much higher than those soft water fish are adapted to, the levels of carbonate hardness are too low for the health of hard water fishes like Rift Valley cichlids, goldfish, and livebearers. So the safe approach is not to use it in any aquarium, and instead draw water from the unsoftened drinking water source in the kitchen. [7]

References:

[1] Matt Clark, Practical Fishkeeping. http://www.practicalfishkeeping.co.uk/content.php?sid=2850

[2] Aldo Palmisano, Chemist, U.S. Geological Survey Biological Resources Division, and an affiliate of the University of Washington in Seattle.

[3] Stanley Weitzman, Lisa Palmer, Naercio Menezes and John Burns, “Breeding and Rearing Mimagoniates Species, Internally Fertilized Tetras,” Tropical Fish Hobbyist, Volume XLIV, No. 12 (August 1996).

[4] Laura Muha, “The Skeptical Fishkeeper” column in Tropical Fish Hobbyist, December 2006.

[5] Dr. Neale Monks, “Use and Abuse of Salt and Epsom Salt in Freshwater Aquaria and Ponds,” Wet Web Media. http://www.wetwebmedia.com/FWSubWebindex/SaltUseFWArtNeale.htm

[6] Stanley Weitzman, Lisa Palmer, Naercio Menezes and John Burns, “Maintaining Tropical and Subtropical Forest-Adapted Fishes,” Tropical Fish Hobbyist, Volume XLIV, Nos. 10 and 11 (June and July 1996).

[7] Dr. Neale Monks, “A Practical Approach to Freshwater Aquarium Water Chemistry,” Wet Web Media.
http://www.wetwebmedia.com/fwsubwebindex/fwh2oquality.htm

[8] David A. Lass, “Using Salt for Freshwater Aquarium Fish,” FishChannel. http://www.fishchannel.com/fish-health/disease-prevention/salt-freshwater-fish.aspx

[9] Cecilia Chen, Badman’s Tropical Fish. http://www.badmanstropicalfish.com/articles/article5.html

[10] Mark E. Evans, “The Ins & Outs of Osmosis,”: Tropical Fish Hobbyist, February 2004.

Byron
08-26-2013, 04:01 PM
Others have correctly said it, but as you asked I will just add my agreement that you should never use salt in a freshwater aquarium except when it is the "best" treatment, and rarely will it be better. For the reason why, I will cut and paste an article I wrote on salt and what it does to fish. I have known aquarist who literally burned the skin off pleco with salt at "normal" dose. The Kordon NovAqua is fine, I used that conditioner for years; I've switched to another, NutraFin AquaPlus, only because I can get it for less money, and being retired on a fixed income this is a concern. Here's the story on salt:

Numbers in square brackets indicate a citation from the applicable reference works listed at the end.

Many fish stores, and other “sources of wisdom” about fishkeeping, will recommend salt as a general "tonic" for freshwater tropical fish. The usual suggested dosage of salt is something like a teaspoon per 5 gallons. As David A. Lass points out, there is not much therapeutic benefit at those dosages. “Salt serves more to assuage the hobbyist's need to ‘do something’ for their tropical fish,” he writes. [8] There is absolutely no need to add salt to freshwater aquaria except as a specific treatment, and even here the sensitivity of certain fish species must be kept in mind. Fish health expert Dr Peter Burgess says he certainly doesn't advocate salt for permanent use: "Unless the species has a natural requirement for salt, then we should not add salt to an aquarium (or pond).” [1]

As the scientific data presented in this summary article indicates, adding salt to a freshwater aquarium on a regular basis will, at best, do nothing of any value at all. But at worst, it will stress salt-intolerant fish, making them more vulnerable to disease and less likely to live a healthy and normal lifespan. To understand why, we need to understand what salt does in water, and how fish are affected. But before this, we must clarify just what we mean by “salt.”

Sodium chloride

In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge) [Wikipedia, definition of “Salt (chemistry)”]. There are mineral salts for most minerals. But for the purpose of this article, we are dealing solely with common salt—what we know as table salt, or rock salt, or aquarium salt. This salt is a mineral that is composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of ionic salts. It is essential for animal life in small quantities, but it is harmful to animals and plants in excess. Marine salt has other minerals in it too, but it is still “salt” for the purpose of this discussion.

Salt is an irritant, which causes the fish to secrete more mucus particularly in the gills where osmoregulation is occurring. And if salt is not predissolved carefully, it can give fish bad burns; this is especially true for scaleless fish, such as loaches, many catfish and some types of eels. [9]

Salt makes the water denser than the same water without salt. The aquarium contains water. The bodies of fish and plant leaves also contain water, just as we do—humans are approximately 70% water. The water in the aquarium and the water in the fish/plant are separated by a semi-permeable layer which is the cell. Water can and continually does pass through this cell; fish do not “drink” because they don’t have to in order to take in water. When either body of water is denser, the other less-dense body of water will pass through the membrane to equalize the water on both sides. The fish must control this process through what is termed osmoregulation.

Freshwater Fish Physiology

Salt definitely interferes with the osmotic regulation of fish and plants. It should be left alone; nature regulated that part itself, by creating freshwater, brackish and saltwater fish. The vast majority of freshwater fish live in waters having no measurable salinity, and this has been crucial in the evolution of their physiology. Fresh water fish differ physiologically from salt water fish in several respects: their gills must be able to diffuse dissolved gasses while keeping the salts in the body fluids inside; their scales reduce water diffusion through the skin; and they also have well developed kidneys to reclaim salts from body fluids before excretion.

Freshwater fish have physiological mechanisms that permit them to concentrate salts within their bodies in a salt-deficient environment; marine fish, on the other hand, excrete excess salts in a hypertonic environment. Fish that live in both environments retain both mechanisms. Freshwater fish concentrate salts to compensate for their low salinity environment. They produce very dilute but copious urine—up to a third of their body weight each day—to rid themselves of excess water, while conducting active uptake of ions at the gills. [2]

The kidneys of freshwater fish have two functions: osmoregulation [discussed below] and hematopoiesis, which is the formation of blood celular components. Each fish species is adapted to the range of salts in its habitat water, and the kidneys function well within that range. The kidneys have to work harder whenever the salt content of the water in which the fish is living is greater than that of the fish’s preference, i.e., the natural habitat. The closer the water is to the species’ requirements, the easier it will be for the fish to maintain proper osmotic levels. One of the myths about the “benefit” of regular addition of salt is that it allegedly maintains an osmoregulatory balance; in point of fact, regular use of salt has the exact opposite effect and can cause bloating due to an osmotic imbalance. [3]

Osmoregulation is the technical term for the physiological mechanism fish use to control the amount of salt and water in their bodily fluids. As the name suggests, it's based on osmosis. Water is constantly passing through the cells of freshwater fish by osmosis in an attempt to equate the water inside the fish with the water in the aquarium. Freshwater fish regularly excrete this water through respiration and urination; the average fish will urinate 30% of its body mass every day. The more salt in the aquarium water, the greater the strain on the fish's kidneys, which in turn adds to the fish's stress in attempting to maintain their internal stability.

And salinity affects the amount of energy the fish must spend to maintain the physiological equilibrium—the complex chain of internal chemical reactions that keep the pH of the fish’s blood steady, its tissues fed, and the immune system functioning. When salinity increases beyond what the fish is designed by nature to handle, the fish must work harder and use more energy just to “keep going.” Laura Muha [4] likens this to driving a car up a steep hill—it takes more energy (gas) to maintain the same speed as driving on level ground, and it causes more “wear and tear.” This increased energy output is wearing down the fish, and the fish is not able to expend this crucial energy on other important functions. The growth rate is affected, a shorter lifespan will usually result, and there will be increased risk of various health problems along the way.

Fish and plants from mineral-poor waters do not appreciate being kept in slightly saline water conditions. Many of the most popular fish today, like cardinal tetra and rasbora, come from soft water habitats. Short term exposure to low salt concentrations across a few days or a couple of weeks may not do them major harm, but constant use of salt in their aquaria could cause problems. [5] In Weitzman et al. (1996), the authors mention that 100 ppm of salt is the maximum that can be tolerated by most characins, and some species show considerable stress leading to death at a level of 60 ppm. [6] To put this in perspective, 100 ppm is approximately equal to 0.38 gram of salt per gallon of water. One level teaspoon holds approximately six grams of salt, so just 1 teaspoon of salt in 16 gallons of water will cause stress, and in some species lead to death.

Another problem is that salt increases the total dissolved solids [TDS] in the water. An aquarium treated with one teaspoon of salt per gallon of water will have an established dose of 2400 ppm. Add to this the TDS occurring from calcium and magnesium salts [these make water “hard”], water conditioners and other additives, and you can end up with over 3000 ppm of TDS. [10] This is intolerable for most fish; even the very hard water in the African rift lakes does not contain more than 600 ppm TDS. And for fish from naturally soft and acidic water environments, this is very dangerous, for nowhere in nature does acidic water exist with a level of TDS anywhere near this. And the deviation from normal osmotic pressure that this creates is very harmful to all fish.

Keeping the tank salty all the time will not help with disease resistance in freshwater fish; in fact, it will actually increase the fishes’ susceptibility to disease and parasites by keeping the fish somewhat stressed all the time, and this weakens the immune system. And at the low level of salt generally recommended for these so-called benefits, there will be no benefit that cannot be achieved solely with regular water changes using a good conditioner.

Some concluding thoughts...

Using salt to increase water hardness

Although plain aquarium/tonic salt (sodium chloride) is sometimes suggested as a good way to increase hardness and improve buffering, it in fact provides very little of either. Marine salt mix, on the other hand, will raise the pH and carbonate hardness quite significantly. But it also raises the salinity, something most freshwater fish do not appreciate. If you live in a soft water area and want to keep hard water fish, using marine salt mix is not really a viable option. Rift Valley cichlids, in particular, seem to be peculiarly sensitive to salt, and elevated salinity levels have been identified as one factor responsible for the dropsy-like disease known as Malawi Bloat (Andrews, et al. 1988). [7]

Fish lore also has it that salt is good for use with mollies, other livebearers and goldfish. David Lass [8] notes that the vast majority of livebearers, including mollies of all types and colors, and sailfins, come from the Far East. They have been raised for generations in water that is moderately hard, and of neutral pH. These tropical fish are very far removed from the wild mollies that came from brackish water. All of the sailfin and lyretail mollies, balloon bellies, blacks, reds, and dalmations do fine without salt. The same with goldfish. The main confusion is that tropical fish need alkalinity. Salt is just one part of alkalinity.

Although NaCl is not composed of any truly "hard" ions, it does raise the total dissolved solids in the water, and these contribute to raise general hardness. This is not well tolerated by a number of fish, especially true softwater fish from places like the Amazon River basin, where there are very few electrolytes of any kind in the water. Salt can have an unpredictable effect on softwater fish, since there are no bodies of water in Nature which are naturally saline (high in NaCl) while being very low in "true" hardness ion concentration (calcium, magnesium, potassium, etc.). [9]

Salt and Plants: When salt is added to the aquarium water, the water inside the plant cells is less dense so it escapes through the cells. The result is that the plant literally dries out, and will wilt. I've so far been unable to find a measurement of how much salt will be detrimental to plants; all authorities I have found do note that some species are more sensitive than others, and all recommend no salt in planted aquaria.

Domestic water softeners: Domestic water softeners do not produce soft water in the sense that aquarists mean. What domestic water softeners do is remove the temporary hardness (such as carbonates) that potentially furs up pipes and heaters by replacing it with permanent hardness (such as chlorides) that does not. While you can pass this softened water through a reverse-osmosis filter to remove the permanent hardness as well, until you have done so, you shouldn't consider the softened water as being suitable for soft water fish.

In fact, aquarists are divided on whether the resulting softened water is safe for keeping fish at all. The odd balance of minerals in softened water is not typical of any of the environments from which tropical fish are collected. While the chloride levels are much higher than those soft water fish are adapted to, the levels of carbonate hardness are too low for the health of hard water fishes like Rift Valley cichlids, goldfish, and livebearers. So the safe approach is not to use it in any aquarium, and instead draw water from the unsoftened drinking water source in the kitchen. [7]

References:

[1] Matt Clark, Practical Fishkeeping. http://www.practicalfishkeeping.co.uk/content.php?sid=2850

[2] Aldo Palmisano, Chemist, U.S. Geological Survey Biological Resources Division, and an affiliate of the University of Washington in Seattle.

[3] Stanley Weitzman, Lisa Palmer, Naercio Menezes and John Burns, “Breeding and Rearing Mimagoniates Species, Internally Fertilized Tetras,” Tropical Fish Hobbyist, Volume XLIV, No. 12 (August 1996).

[4] Laura Muha, “The Skeptical Fishkeeper” column in Tropical Fish Hobbyist, December 2006.

[5] Dr. Neale Monks, “Use and Abuse of Salt and Epsom Salt in Freshwater Aquaria and Ponds,” Wet Web Media. http://www.wetwebmedia.com/FWSubWebindex/SaltUseFWArtNeale.htm

[6] Stanley Weitzman, Lisa Palmer, Naercio Menezes and John Burns, “Maintaining Tropical and Subtropical Forest-Adapted Fishes,” Tropical Fish Hobbyist, Volume XLIV, Nos. 10 and 11 (June and July 1996).

[7] Dr. Neale Monks, “A Practical Approach to Freshwater Aquarium Water Chemistry,” Wet Web Media.
http://www.wetwebmedia.com/fwsubwebindex/fwh2oquality.htm

[8] David A. Lass, “Using Salt for Freshwater Aquarium Fish,” FishChannel. http://www.fishchannel.com/fish-health/disease-prevention/salt-freshwater-fish.aspx

[9] Cecilia Chen, Badman’s Tropical Fish. http://www.badmanstropicalfish.com/articles/article5.html

[10] Mark E. Evans, “The Ins & Outs of Osmosis,”: Tropical Fish Hobbyist, February 2004.

gronlaura
08-26-2013, 06:49 PM
I would suggest 50% water changes every week, along with cleaning the substrate - at least half the tank at a time. A well-fed pleco is going to poop a lot. I have 4 BN's in different tanks and this is one of my favorite fish. Sorry you are having such trouble with yours.

+1 big time to 50% PWCs. And if you had 40 ppm nitrates and did a one time 25% PWC, you would still have 30 ppm, not 10 ppm. There's no way you could change only 25% of the water and have a 75% reductions in nitrates. If you are only doing 10% weekly changes, your nitrates would be 36 ppm after the PWC. And as stated by others, do not add salt to the tank.

I would say the ammonia, nitrates and fear of the shark (highly stressed pleco) are what is doing in your plecos. If you want a bristlenose, the shark needs to go and you have to keep on top of your PWCs (50% weekly) to provide good water parameters.