All my cichlids died in 48 hours

[knowles_101]

Hey guys I have a 30 gallon tank with 6 african cichlids...well used to have 6 african cichlids. Anyways the tank was cycled and everything was great for a few weeks, then I did a water change and did a bit of vacuuming of the sand/cichlid gravel mix and withing 48 hours all my fish were dead. I tested the water twice with no signs of amonia, nitrate or nitrite,the PH and water temp were perfect.

My dad told me that all the fish were swimming at the top as if feeding or gasping for air. All my water tests were fine so I tested the tap water and that was good as well.

Any idea what could have killed my fish?

 

[djmodifyd]

did you use a bucket when you did a water change?

if so...did someone use that same bucket and put soap in it?

 

[blackwolfXKAV]

Hey guys I have a 30 gallon tank with 6 african cichlids...[What species were they; just saying african cichlid does not help. try and describe them please.]well used to have 6 african cichlids. Anyways the tank was cycled and everything was great for a few weeks, then I did a water change[how much?, and was this the first water change?] and did a bit of vacuuming [did you disturb too much of the beneficial bacteria in your substrate, perhaps?] of the sand/cichlid gravel mix and withing 48 hours all my fish were dead. I tested the water twice [which water, the tap? and when did you test, before or after the water change? also, DID YOU ADD DECHLORINATOR?] with no signs of amonia, nitrate or nitrite,the PH and water temp were perfect.

My dad told me that all the fish were swimming at the top as if feeding or gasping for air. All my water tests were fine [can you post?] so I tested the tap water and that was good as well.

[what did the fish look like when dead? were their gills red?]

Any idea what could have killed my fish?

too many variables here, ie; what was the tanks history as far as maintanance goes, etc, see red notes.

hope this helps, Black.:cool2:

 

[Cathy G]

How long had it been since you did a really deep gravel vac? Perhaps a pocket of toxic anerobic gas or a bubble was released into the water - that can kill fast. How deep is your gravel/sand and do you have malaysian trumpet snails in the tank? (They hang out in the gravel and keep things stirred up a bit, sometimes this helps prevent those pockets of gasses...)

Hope you can figure this out!
Cathy

 

[knowles_101]

ok the amonia, nitrite and nitrate were all 0 and the PH was 7.8 and the water temp was 78F. I did use a dechlorenator but I also tested the tap water which had 0s accross the board.

I had done weekly water changes 25-40% water change. The tank had been cycled and running with a bioload for about a month.

Most of the gravel was coverd with big rock so I was only able to vacuum a small area of the gravel.

The cichlids were all yellow labs.

 

[jm1212]

Hey guys I have a 30 gallon tank with 6 african cichlids...well used to have 6 african cichlids. Anyways the tank was cycled and everything was great for a few weeks, then I did a water change and did a bit of vacuuming of the sand/cichlid gravel mix and withing 48 hours all my fish were dead. I tested the water twice with no signs of amonia, nitrate or nitrite,the PH and water temp were perfect.

My dad told me that all the fish were swimming at the top as if feeding or gasping for air. All my water tests were fine so I tested the tap water and that was good as well.

Any idea what could have killed my fish?

aggression and stress from it probably did them all in.

 

[Dixon]

i too think maybe contamination of some sort my be the culprit.
the bucket or hose used may have been used for something else recently, i would check down this route it is easily done.

 

[wataugachicken]

you should have been showing nitrates in the water. . .that's odd. i also agree with contamination. when you changed the water, was the new water at or near 78?

stress and aggression are possible but i doubt it, all of them dying within 2 days looks more like a water problem. if stress, wouldn't it be one or two at a time dying slowly?

 

[Jayhawk]

I agree with wataugachicken - a cycled tank does show nitrates. How old are your test kits? Are they kits are strips? Do your tests of the tap water match city tests (you can call them and check)?

How did you cycle your tank? This last question could be key as I suspect your tank wasn't really cycled.

Then again, the contaminant in the bucket theory is a possibility, too.

Eric

 

[mooman]

aggression and stress from it probably did them all in.

That's a ridiculous statement. Although the poster did not state the size of the yellow labs since he has only had them for a month I would guess standard fishstore size of about 3inches. This in no way constitutes overstocking (in the future yes, but not if they are still growing out). Aggression or stress would also not kill every fish in such a short period of time.

I realize that putting too many large fish in too small a tank is a major pet peeve of many of the serious hobbiests on this board, but a post like the one above offers no helpful advice and is in my opinion a low blow.