No water change / No clean experiment at 1 year

[qroberts]

My no clean, no water change experiment 1 year later;

Equipment:

37 gallon tall glass aquarium
Penguin 350 dual biowheel with ¾ bioballs, ¼ denitrate granules and modified outlet cowlings
250W visitherm immersion heater
48W t5 lighting ½ 10000K ½ plant pink
Ecocomplete black substrate mixed ½ with home depot desert sand
API master freshwater test kit
Town of Cambridge MA, water (treated with chloramine)
Flourish plant supplement
Cheapest flake food by weight

Florae / Faunae:

Hornwort, floating
Duckweed, floating
Assorted medium lighting plants at 50% bottom coverage
Mixed gender tiger Endler’s
Cherry barbs
Giant danio (recent)
Red Cherry Shrimp
Assorted stowaway snails

Hypothesis : A planted aquarium with adequate biological filtration will not require water changes to maintain nitrogenous chemical balance.

Results: Well, it’s been a year since I started this experiment. Initially I scoured the internet concerning “balanced aquarium” / “no water change” systems with plants, fish and inverts and was disappointed by the information available. Most of the positions stated in forums were little more than heresy with no data to back up claims such as:

1. You have to change the water periodically to have a healthy fish tank.
2. Chloramine must be removed from tap water or the fish will suffer.
3. Duckweed is the devil and should never be introduced.
4. Nitrate will always build to intolerable levels even in heavily planted tanks.

As a physician and scientist the ideal approach to determining what was true and what was false was experimentation.

I determined the following:

1. An aquarium can be maintained in a healthy state without water changes for up to one year. Now, let me clarify what I mean by healthy: undetectable ammonia, nitrite, nitrate, no fish disease or mortality, no algae (Crystal clear water and glass, no cleaning), no odor. Granted the fish I keep are small, self propagating and relatively hardy, however, I have not had a single death, and have observed robust breeding. Also, I did not account for non-nitrogenous, soluble, non-volatile contaminants which would of course, be expected to build with time. I would imagine that larger aquariums fare better in that the ecosystem would be expected to be more stable.

2. Chloramine need not be removed from water in order to keep a healthy aquarium. I have never treated the water I add to the aquarium and have observed no deleterious effects from one to two gallon top offs. Granted, again, I keep relatively robust fish, this experience may not duplicate with more delicate specimens. However, chloramine is a relatively non-toxic chemical (to multicellular life) which does dissipate over approximately one month. As such levels would be expected to be highest during the new tank phase and maintained at a low equilibrium with top offs.

3. Duckweed is a miracle plant. It soaks up nitrogen so quickly that other plants need supplemental fertilization. As it reaches confluence on the surface of the tank, one can simply skim it off and throw it in the composter thus permanently removing that nitrogen from the aquarium cycle. Filter clogging can be avoided with two simple steps 1) place a course sponge over the intake (needs cleaning every 3 weeks) 2) place cowlings over filter outlets which extended from the surface to several inches below (this keeps the duckweed from being caught by the current and pushed underwater and thus avoids clogging the filter sponge too quickly. I made mine out of 2 liter soda bottles).

4. Following establishment of the nitrogen cycle and adequate planting, nitrogenous waste has remained steadily undetectable even as fish population rises.


Observations:

Plant growth was initially slow, peaking at the 6-8 month mark. At this point bottom plants (with the exception of Madagascar lace surprisingly) began to suffer. CO2 supplementation with fermentation bubbler and fertilization did not seem to help. Hornwort and duckweed continued to grow explosively. I have three theories as to why this is: Inadequate lighting due to floating plant overgrowth, iron deficiency in substrate (buying iron supplementation as we speak), superior nutrient competition from hornwort and duckweed.

Shrimp initially reproduced at a staggering rate and were seen swimming all over the tank. Now only the largest, most established shrimp remain. I suspect either fish predation or copper deficiency is to blame.

The endler’s fecundity is incredible. They seem to bear every 2 months roughly 6 spawn per female. I have no idea how many survive, but I now have 12 adult males from a previous 3 and 14 adult females from a previous 6. We’ll see how they handle some giant danio predation (they’re like miniature tuna, fast and voracious). At some point they will exceed the biological capacity of the aquarium and I will surely see nitrogen spikes. At this point I will either have to give them away or feed them to the cat as they are born, which sounds like a hassle.

I do have a thick carpet of algae growing in the outlet of the filter in a lighted area, but I feel this only enhances filtration. Additionally, white mold (probably penecillium due to my cheese making) has established a colony on the above water portions of the bioballs, again I feel this can only enhance filtration.

Snail population initially increased exponentially with long cone shells dominating, followed by ram horn shells, followed no by odd, thin shelled, brilliant red mantled snails in moderate numbers. None of them were introduced on purpose.

The fish have consumed roughly 500g of flake food during the year. The large shrimp have even learned to hang out near the surface and snag flakes. I suspect that is why these are the only remaining shrimp, namely, the bottom feeders receive insufficient nutrients.

The odor of the tank has progressed from outdoor pool to soil to algae to turtle water to river to ocean smelling during the year. The longest stable odor was river. Ocean is new as of this month and I think probably reflects differential bacteria growth in the warm weather (we have no AC).

I realize the rootbeer bottle fermenter is less than aesthetic. In an entire year, I have yet to pick up black construction paper for a backing, because I am extremely lazy.

[Brhino]

Interesting stuff, thank you for sharing!

Since we just had a bit of a blow-up here on the forums about the wisdom of not doing water-changes, I wanted to point out that the setup the OP created was a very specialized case:

• He stocked a variety of fast-growing plants and provided conditions for high growth (good lighting, fertilization and carbon additive), thus allowing for strong nutrient absorption and removal.
• He stocked only very small fish, and low-bioload invertebrates.

Just because things are going well for him after a year does not mean it's a good idea to neglect water changes in your heavily stocked unplanted tank.

I do have a couple questions/comments for you, qroberts:

• How long ago did you add the giant danios, and how many did you add? I should think that adding them will substantially increase the bioload in the tank, especially as they grow to their adult size, and the balance you have achieved may be overcome.
• You say that chloramine poses no threat to the tank. Conventional wisdom is that chlorine and chloramine are most harmful to the beneficial bacteria, rather than to the fish themselves. However, apart from the initial filling of the tank, you've only been doing small top-offs? It seems likely that rather than proving that chloramine is harmless, you have proven that it is not threatening in small quantities. I imagine that if you did a 50% water change with untreated water the results may be considerably different. What do you think?

[qroberts]

Didn't realize there had just been a big argument concerning no water change tanks on this forum. I certainly don't intend this post to rekindle any animosities. Rather I intended it to fill a void in the information available to the new aquarium enthusiast concerning maintenance and the establishment of a new tank. I am of course, as a scientist, open to all other points of view and I do clearly see the validity of counter arguments that water changes can improve the health of a tank. I merely wanted to see whether my own aquarium could be maintained in nitrogen balance and with a moderate fish load without water changes.

That said:

1. The danios I added today, three of them. I've considered that as they reach adult size they may throw off the nitrogen balance and in that case I suppose I'll be forced to perform water changes or remove fish and give them away. I thought I would try natural population control before physically removing fry because that could be a serious hassle.

2. As for chloramine, I agree that it should pose almost no threat to multicellular life at the concentrations of municipal tap water. As for it's effect on bacteria, the chemical is designed to limit bacterial growth in the water supply and hence would be expected to perform this function. However, it by no means removes all bacteria from tap water. As a avid brewer I've seen many instances of non-boiled water additions causing bacterial contamination and it has long been a concern with surgical scrub ins, that tap water is used to rinse one's hands, prompting the development of no water cleansers.

During the initial tank setup, the water was 100% city tap. I performed a fishless cycle for 2 months with added ammonia (from the hardware store). The only bacteria that could have existed at this point were airborne, fomites (surface contaminants), and the bacteria contained in the "black water" additive the eco complete substrate came packaged in. As you can see from the graph provided, ammonia levels spiked initially, as would be expected. Within 2-3 weeks the levels precipitously decreased with a concurrent spike in nitrite and shortly thereafter nitrate. This indicated that a bacterial nitrogen cycle had been established. I have considered that the chloramine could have had time to dissipate in this time frame, or at least decrease in concentration. I've wondered what would happen to my bacteria if I suddenly added 50% new water. Would they die? Or would they be unaffected? It's an experiment that I might try in the future, although not with a nicely stocked tank.

Like all bacteria, one would expect aquarium bacteria to develop resistance to antibiotic treatment. Luckily, chloramine and chlorine exhibit bactericidal activity in a physical sense rather than interfering with any specific bacterial pathway as say, penicillin dose. Therefore, bacteria are largely unable to develop resistance to chlorine in the strictly genetic and epigenetic sense in which they become resistant to antibiotics. However, they can develop a physical defense to a physical insult and this is the formation of a bacterial biofilm, a mucus-like coating in which a colony of bacteria resides. For a real world example look no further than the plaque on your teeth, which no amount of mouthwash alone will disrupt. These coatings can make bacteria highly resistant to traditional antibiotics and physical antibiotics alike. In an established filter one might expect deeply entrenched, biofilm bacterial colonies to be much more tolerant of chloramine than newly established colonies in a recently started aquarium.

I hope this adequately addresses your questions and some of my rationale.

[smaug]

No argument,we are all in agreement that water changes are a required part of fish keeping. I wish to congratulate you on your experiment where the objective was to prove that fish can be kept for a whole year in a state of neglect with just a few losses of life. I propose a new experiment where you keep the tank properly and with the concern that living things deserve.What a fat cat you will have then with all the fry it will get to consume.

[Cliff]

There’s two aspect about your test that I was wondering if you could provide some more detail on (and I apologize if I missed it)

How would/did you predict the long-term effects on the fish and shrimp? Even during your short one year period, you experienced losses. From I have read, water changes replace trace elements required by the fish and remove other substances (like hormones) from the water. Based on what I have read, that is why the Walstad Method suggests water changes as needed. Just wondering if this is now a concern or factor in your experiment.

Do you have any supporting research about the bacterial colonies building resistance to chloramine and chlorine that you could share? I read your reply to Brhino but I still would like to know more. As that really does go against traditional knowledge and research that I have read to date, I would be interested to read some more about this.

At any rate, this would be a set-up for someone with more advanced knowledge and experience in the hobby

[qroberts]

I would just like to clarify that I have not had a single fish death during the year not counting fry which were consumed by tank mates and whose numbers I cannot estimate (perhaps due to covert cat predation ). I have not seen any dead shrimp, I just can't find as many to count. None of the fish have fin or body disease and all behave normally and feed enthusiastically. The point of the experiment was not to prove that you shouldn't change your tank water, just that, situation depending, it won't kill your fish if you don't. And in response to the comment that they are neglected, I would say they are far from neglected as I have kept careful tabs on chemistries, temperatures and behavior throughout the year and was ready to institute water changes if anything worried me. And this isn't my first aquarium, more like my 12th.

1. Now, I really did not know what the effect of infrequent water changes would be on the fish and shrimp. I suspected that the shrimp would fair less well, but they flourished until the fish population increased dramatically. I had heard that trace elements might be replenished by water changes and I wondered about this, however, seeing as the fish are fed the remains of other fish, one would expect these elements to be contained within the flake food should they be so vital to fish health and metabolism (e.g. they would surely be sequestered in the fish used to make the flakes). Furthermore, the mineral content of municipal water varies so dramatically from source to source that it would be near impossible to conclude that all municipal water sources happen to contain exactly the minerals which aquarium fish need to survive (e.g. aquifer vs reservoir vs desalination vs river).

As for removing hormones, from the water system there are two possible sources. Synthetic hormones (not recombinant or endogenous) may have an unnaturally long half life. Additionally many common industrial chemicals have hormone like properties. However, these compounds would not be expected to be produced within the aquarium environment itself and would more likely be present in the municipal water supply rendering water changes ineffective at removing them. Endogenous hormones, as would be expected to be produced by the fish themselves are designed to carry signals within the bodies of the fish, and subsequently broken down and excreted. Within the blood, cells, or interstitial space of living creatures, hormones (either protein or cholesterol based) have a half life ranging from minutes to days. Furthermore, most are selectively broken down soon after performing their function and only metabolites are excreted. Should intact hormones reach the external environment, one must keep in mind that these are organic molecules based off of useful substrates (cholesterol and amino acids) and they will be readily taken up and utilized by other life forms (bacteria, algae, plants) in much the same way as a thimble of egg whites or yolk would be. In fact, there are few compounds I can think of, which could build up in the aquarium due to living processes that could not be utilized by some other part of the energy /life cycle.

2. Research concerning biofilms is robust to the point of having an overwhelming number of research articles. I picked out some of the more straightforward and general ones. In terms of biofims and aquaria, I'm not sure any research exists outside of specialized journals (e.g. for large public aquariums) and if any existed beyond that I would be dubious as to the quality of the journal.

Municipal water system ecology. If you can get full text has interesting discussion on nitrifying bacteria specifically removing active chloramine breakdown products.
http://www.sciencedirect.com/science...58166906000656

Good early paper on mechanisms of chloramine resistance
http://www.ncbi.nlm.nih.gov/pubmed/1444406

Review of quorum sensing and biofilms
http://www.ncbi.nlm.nih.gov/pubmed/20179876

More on water systems colonizations and resistance
http://www.ncbi.nlm.nih.gov/pubmed/12957935

[Surfdog]

Quite the read! This explains alot on how I was "lucky" I guess you can say on my 1st tank, oh so long ago. A 33 Gallon heavily planted, with just a Jack Dempsy and an Oscar. The Tank ran for 2 years, Never a water change, just top off's with city water. I did clean the Fluval Can every 3 months as well. Ended up giving it all away due to a move to the West Indies. Thanks for explaining the why they survived...

[Honey Badger 1]

Maybe you should research Diane Walstaad.

If you look around the forum you will find the occasional statement that plants use up nitrates and there are several members here you have little to no trates because of their heavily planted tanks.
If you look around the forum you will find the occasional statement that a heavily planted and appropriately or lightly stocked tank will have little to no nitrates.
If you have little to no nitrates you don't have to do as large or as many water changes. The problem is, most people, especially new to the hobby people, don't have the knowledge or the will power to keep a heavily planted and appropriate or lightly stocked tank. So we give advice to that level.
Nitrates are not the only reason we change water. The fish give off hormones, there are dissolved solids in the water, just to name a couple off the top of my head.
We remove chloramines from the water to protect the bacteria not the fish.
It's fabulous that your fish survived for a year. Many fish in this hobby can live 10 or more years when properly kept in a clean, healthy, properly kept environment. So your experiment using living creatures has really only begun, get back to us in 9 years... Time will tell.

[qroberts]

We will see how long they persist in this state. However, I am not performing a survival experiment, namely I won't come back 3 years from now and say "welp, all the fish are dead and it took a long time!"

As soon as I get even a hint that one of the fish is sick, or just is not behaving in a normal fashion I'm calling the experiment.

After all, science and sadism are not mutually inclusive