!!!!!! tank crash but all readings are good?

[sniggir]

I just lost all but 2 fish in my daughters tank..... but all of my readings are good amonia 0, nitrate 0, ph 9, gh12.... they seem to be gasping for air. I have done water changes... this happened in a 24 hour time frame I looked at my larger guy and his gills are all red.. does any one know what this could be?

thx Pat

[beowulf]

What about nitrite?  Did the heater go crazy what is/was the temp in the tank?

[aroc]

there must be something really wrong for cichlids to be going that fast.. I am inclined to think it be nitrite as well since nitrates are low

[oenology]

Low oxygen levels is also a possibility. I have a few tanks where my fish will be gasping if I don't have a bubbler - high stocking levels

[sniggir]

but the wierd thing is I just did a wc 3 days ago.. the only thing I can think of that is different, was I forgot to put there food into the freezer the night before..maybe I gave them food posioning lol?    ahhhh and I did 3 changes yesterday 1 in the morning when I saw the problem... of 25% my wife did one 4 hours later of 25% and then I did one of 90% when I got hope and I checked the temp to make sur that the water I was adding was the same....ahhhh

[beowulf]

Never thought of fish being able to get food poisoning.....ummm

[bitterman]

Sorry to hear things. that tank had alot of rock in it is it possible a fish died int he caves and was decomposing? Kiling the other fish? Probably not, just curious

Also how old ar ethe test kits? Maybe they are not giving proper readings?

[mseguin]

I agree with oenology that low oxygen levels seems to be the culprit

[KLKelly]

I thought you could tell from the gills - i thought that purple gills indicated nitrite poisoning and paler/pinkish gills meant oxygen deprivation.     I might be oversimplifying what I've read in the past.  Just had this in my mind as indicators for a while.

[markw]

If the O2 level is low(which is a real possibility) try a dose of hydrogen peroxide 5-10ml/10gal. Dilute it first in the water to be added to the tank and try and pour it into the filter stream. Continue high levels of aeration, but you need to determine the source of the hypoxia. Physiological hypoxia can be caused by gill parasites and this also could have led to the deaths. If the temperature increased for whatever reason O2 levels will go down.
I would suspect if the numbers look good and the temps are O.K. then some pollutant affected their gills and/or a parasite developed. The frozen food should never be used again if left to thaw. The high protein levels in the food will spoil and is paramount to eating spoiled beef or chicken.
Hope this helps
markw

[sniggir]

Thx guy I am going to trying arateind the water today but I thought that doing the water changes would replace the water.. I change my water 25% every 7 days... the gills were definatley purple.. there are 3 left so I will try the bubbler

[succinctfish]

Back to basics question, have you checked your filter?  Is it working properly?  I don't know what kind of filter you have, but  I have experienced times where the intake on the canister filter has become obstructed with plant debris, or if I have a sponge on the intake, I find it needs to be taken out and cleaned.  The corydoras let me know that something is slightly awry, just thought I throw that out there as something to consider. 

[aroc]

sometimes doing too much too often is not good either, like myself my fish at this time where I cannot see them are lucky if I do a water change once a month.. and I haven't even touched my filter in about a year and a half.. as long as the water is coming out of the output at a reasonable clip that's good enough for me.. no fatalities in a few years with that substandard effort

[sniggir]

I will check the the intake It is a ehiem ecco good upto 60 gal I did notice that the water flow wasn't the greatest.. I think I will clean the tubes and check the impeller.
thx for the info guys