should I change?

[marc4]

My tank is finally cycling, but I'm still dealing with a problem that I think started long ago. Because I had set up my tank with gravel and plastic plants before I realized I would be getting cichlids, it is causing a problem. For months, brown, slimy and non algae looking material was building up fast. In the beginning, I was feeding mainly flakes, and probably too much.
That along with series of filters not equipped to deal with the type or number of fish, let most of that crap on the bottom, sunken into the gravel.

I took out the two pieces of "aquarium furniture" that grew the brown material really fast and though things were better. I added another layer of rocks so everyone had their own space to retreat to each night. With the exception of one fin nipping incident, there has been no violence. I lost one fish, the one that had been nipped but had grown the fin piece back. She had been spending all her time at the top, head up, tail tail down, perpendicular to the surface. I did a thorough exam on her post mortem and found no lesions on the body or in the gills. She may have lost a little weight, but not enough to notice unless you looked closely.

After her death, everything was fine for a few weeks. Now, in the past month or so, a second fish was at the top, pale gills, irritated vent and a very slight area of edema just in front of the vent. Catching her and isolating her in a deep tupperwear sweater box with air stone and filter was so stressful I was afraid it was going to kill her. I opted for giving her an injectable antibiotic. She improved markedly, spent her time on the bottom or in her cave, swam around and ate some. Two weeks later, she began to decline at which point I gave her a second injection, and again she improved markedly and was actually almost normal. The antibiotic come with the possibility of renal failure, but I felt it was warrantied. Now she is starting again, but has three tiny white spots about 2mm below her dorsal fin. The dots are bilateral and in the same place and number on each side. Fungus doesn't act so democratically.
Her gills are pale as well. I may lose her, but suspect the underlying cause is prolonged stress from really crappy water with something growing that shouldn't be there.

When I took my fluval 306 apart, it was completely covered with that brown slime and had blocked close to 90 percent of the large particle sponges. I must have sunk over a thousand into this tank trying to make it work right and getting the fish what they need. Even so, I'm wondering if I need to take the tank down to nothing, all the fish in the tupperware sweater box with air stones, remove the gravel, replace it with sand and start over. My fluval has ceramic rings for BB, and the canister can be locked off with the water still inside the canister so I can keep them moist.

Sorry this was so long, but I thought history was important. When I agitate even a two inch area of gravel, it literally makes the entire forty gallon cloudy. I''m afraid that if I don't do something, over time it will stress my fish and take them from me prematurely. Since I am confined to the room anywhere from 19-20 hours a day (chronic pain), these fish mean a lot to me. Both individually and as a group. They have their own personalities, add color and not a day goes by that they don't elicit a smile or chuckle. They also give me a reason to push through the pain.

please help. I'm open to opinions and experiences. The tank temp is at 80 degrees. Most are cichlids from lake Malwali with the exception of my petricola cat and very small congo black calvus, making twelve fish in total, mostly males all of different species.

thanks
marc4

[angelcraze2]

I am so sorry of all your struggles. To make this short, I support your idea to replace substrate and 100% water. Preserve water and bacteria in the Fluval.

Holding the fish while you clean the main tank will be a challenge. I think you'd want to keep cichlids separate, but how long do you think this might take to clean out?

[Rocksor]

I would do barebottom for the first 2 weeks to see if you have any issues. You could put back the other decor.

[angelcraze2]

Going bare-bottom for a while is a great suggestion.

It might be easier to find a rubbermaid close to the footprint of your 40g. You could reuse it for storage later. That way you could take the heater from the main tank, you could even run the Fluval on the bin. It would save you from feelling rushed getting the main tank cleaned out. To reinforce the top of the bin (if needed) I cut a hole (flap) in the cover for access and the cover along the perimeter helps keep these rubbermaid from bowing.

A member here recently got 55g heavy duty bins to hold her fish. She's doesn't even have a top on them to hold it, only a screen top. She's actually had her fish in tubs since October and is slowly setting her new tanks up after moving houses. Just to give you some confidence while cleaning the tank out.

[fissh]

What your describing sounds like poor water conditions. I don't think it's your gravel. I think your over feeding. Do you have any tests? A 40 gallon with Africans with just a 306 is under filtered. If this was my tank I would take all the ornaments out and scrub them in hot water with a brush. Next I would gravel vac the tank once a day taking out half the water, until the fish look better. Then I would look into getting more filtering and not feed as much. When I had a LFS with 230 tanks, I only had to break down 3 tank in a 23 year period. So breaking it gown is the last option.

[Rocksor]

What your describing sounds like poor water conditions. I don't think it's your gravel. I think your over feeding. Do you have any tests? A 40 gallon with Africans with just a 306 is under filtered. If this was my tank I would take all the ornaments out and scrub them in hot water with a brush. Next I would gravel vac the tank once a day taking out half the water, until the fish look better. Then I would look into getting more filtering and not feed as much. When I had a LFS with 230 tanks, I only had to break down 3 tank in a 23 year period. So breaking it gown is the last option.

The overfeeding has already led to too much crud in and under the substrate, hence the cloudiness after gravel vacuuming a 2" area. He's reached the last option.

[SueD]

What is your normal tank maintenance schedule? Filter cleaning schedule? When you say "when I agitate ... gravel it literally makes the entire forty gallon cloudy" do you mean when siphoning or just moving it around? I've found that gravel is usually easy to deeply siphon and remove detritus.

[angelcraze2]

If the gravel bed is deep, it may be very difficult or impossible to remove all the detritus from initial overfeeding. The OP has switched to pellets from flakes, the flakes really mucked up the tank because they were sucked into the HOBs he originally had as filtration. He has since changed his feeding habits, but damage is done. From the OP's description of swirling a 2" gravel area and clouding the entire tank, it sounds pretty cruded. This has been going on for months, his fish are feeling the burn, I feel a complete removal of substrate is needed here.

@marc4, you can wash the gravel after removing by rinsing until crud is no longer washing out. I would leave it soak in hydrogen peroxide to disinfect afterward. Gravel is not the worst unless you let it accumulate too much debris. Regular deep gravel siphoning every week at least is needed. I also suggest a very thin layer if going with gravel. With sand, the debris rests on top, or is moved to one area with filter flow. It makes siphoning the tank bottom much easier. But bare-bottom ensures no crud will get stuck and helps diagnose other issues if there are some.

[Rocksor]

1-1.5" substrate is fine with no plants going forward (clean all gravel)

1/4 bottle of hydrogen peroxide per 3 gallon bucket should be enough to disinfect gravel (1 gallon of gravel in bucket) for 24-48 hours. Detritus matter is a breeding ground for columnaris bacteria, so I would disinfect the gravel after rinsing with tank water to remove crud.

[fissh]

Sorry to disagree with all of you guys, but a 2 inch gravel base can be completely vacuumed out. It might take 10 times but I feel it's less stressful for the fish than netting them and putting them in a tubberware box. If the OP still has HOB filters he should put them back on the tank in addition to the 306 canister.