We have a 55 gallon cichlid tank, it has been set up for about a year. Life has been good, fish happy, etc. I want to say peacocks, but I really don't know, other than a couple of yellow labidicromus and a red shoulder peacock. Anyway, tonight my hubby fed the fish, probably a little too much, I kid you not, 1 hour later all dead fish, except the pleco. Any thoughts? Can one over feeding kill an entire tank? What else should we be looking for? Thanks!

By Melana on Friday, October 8, 2004 - 07:59 am:

I think there's probably something else wrong, I've never heard of a little over feeding killing that many fish. I'd say make a call to the pet store you bought them from, they will be able to tell you more.

By Kernkate on Friday, October 8, 2004 - 08:26 am:

I not a real expert we do have a fish tank, but I don't think they could have been all overfed. I think maybe they might have gotten a disease or something that affected the whole tank. Just my thoughts.

By Mara on Friday, October 8, 2004 - 09:07 am:

Was this a new food? Had they been fed from this container before? If they have been fed from it in the past then I think the problem was there before the feeding. If it was a brandnew container of food then it might be the food.

Mara

By John on Friday, October 8, 2004 - 10:23 am:

Some good questions above regarding the food...

I kept (and bred) African cichlids for several years...

What kind of filtration and aeration did you have? Sponge? Other?


Cichlids typically like a high PH > 7.5
At this PH, ammonia (from waste products or food) is very toxic to fish and needs to be handled by biological filtration in a tank (Sponge, under gravel or similar).
Did you have a filter like this in the tank?

How often (and what method) was the tank cleaned?

Usually a layer of crushed coral is used in the bottom of cichlid tanks to maintain water PH.

What kind of gravel was used in the bottom of the tank?

I suggest you purchase an Ammonia test kit (about $5-$10) at a fish store and test the water in the tank.

An established tank should show zero ammonia level. Any presence of ammonia indicates that you don't have sufficient biological filtration (which should convert ammonia to harmless byproducts).

Here's an excellent resource link on the subject:
http://www.americancichlids.com/filters.htm

By Kaye on Friday, October 8, 2004 - 03:52 pm:

We run a fluval carbon I think filtration, we have special gravel. We do water changes every two weeks, about 10 percent. We have had african cichlids for the past 10 years now, we have just never had this happen. We have fed out of the food container about a week, but it really is like they were poisoned. They were just fine and then suddenly all belly up. Our pleco is still looking good though (he doens't eat the food), weird.

By John on Friday, October 8, 2004 - 06:55 pm:

Was any extensive cleaning done on the tank in the last couple weeks? Anything new (decorations or equipment) introduced to the tank in that period?

I'd sort of approach this like a murder mystery...trying to figure out what, if anything, has changed recently.

How many (and how large) were the fish that were in the tank?

When was the most recent water change?
Do you use any chlorine neutralizer when you add water?

By Kaye on Friday, October 8, 2004 - 11:24 pm:

Last water change was two weeks to the day yesterday. We do fairly regular changes, every 2-3 weeks, with a syphon and clean the gravel. Nothing has been added to the tank in at least 6 months, no rocks, no plants (we don't have plants), no fish. We had 2 clown loaches (4 inches), we had 1 very lg pleco, we had about 10-12 4-6 inch assorted african peacock cichlids. I talked with the food company, they want to test the food. I had my water tested, ammonia levels were great, nitrates were horrible. So looks like a nitrate issue, but I am not sure why it would so suddenly kill them. But my best guess is the levels got too high for some reason...this needs looked in to and then the adding of food just did them all in.

By John on Saturday, October 9, 2004 - 12:07 am:

High nitrates indicate you need to increase the frequency of your water changes but I don't think that's what killed them.
Did you get tests for Nitrite? Nitrite is the breakdown product of Ammonia and is just as toxic.

What was the water PH?

15 large fish in a 55 is a lot of fish. You need excellent biological filtration for that many fish.

I'm not sure I understood about your filters...
Do you have an undergravel filter or just the fluval? The fluval is just a chemical(carbon) filter and won't do much to convert ammonia(the fish waste) to nitrite and then to nitrate (this process is called biological filtration).

If you have just the Fluval, you should add a simple sponge filter driven by an air pump.

Otherwise, you might be getting an ammonia spike everytime you feed the fish that takes hours to dissipate (that stresses and eventually killed the fish).

Was the fluval cleaned with the last water change?

By Kaye on Saturday, October 9, 2004 - 09:00 am:

Yes we have an undergravel filter, yes we cleaned the fluval (it a big one, fills up one entire half of the bottom of the tank. We also have two power heads that run, not sure what they do. We have had this tank for at least 10 years, it has almost always been set up just like this, same number of fish, we have actually never lost a fish, other than new entry times. So I think that is what perplexes me most. We felt like we had it going just fine. They did not tell me the ph, they dipped three sticks and said the nitrates were high but everything else was fine.

By Momoffour on Sunday, October 10, 2004 - 04:08 pm:

Kaye my dh also has a 55 gallon cichlid tank. The only thing I could think of was maybe the temp changed.

By John on Sunday, October 10, 2004 - 07:47 pm:

Sounds like you are doing the right things...

Here are some general fish maintenance tips for everybody:

Get a set of water test kits. You can order these mailorder for $5-$10. I'd recommend PH, Ammonia, and Nitrite.

Test the water in your aquarium once a week(or right before a water change). If you see ANY ammonia or nitrite (or a drop in PH) it means your biological filtration has been compromised and you need to find the cause right away.

When cleaning your tank, don't clean your undergravel or other filters too thoroughly. That thin layer of bacterial slime is what is eliminating the ammonia waste produced by your fish.

Be sure to use a chlorine neutralizer when you do a water change. The chlorine can kill the bacteria in your bio filter (not to mention your fish). I like Stress Coat (a brand name)

Age the water going into you tank if possible and use a carbon filter in your tank to remove toxins. Water departments sometimes add chemicals that will kill your fish without a carbon filter to remove them.

If you have soft water (low minerals and PH) use coral gravel (just for cichlids) to raise and stablize PH.
People with very hard water will need to soften it if they have fish like Discus.

Good luck