lots of dead fish

[Mstrildy22]

my chiclids are all dead and the ph and nitrate are all fine what could it be?? please help me on this one the amonia level is 0 and the nitrite is 2 they are in a 40 gal tank i have a convict in there with themshe is dead too the orange ones were first to die then the kenyis then convict but it all happened over 1 day they were acting fine in the morning i came home they were all almost gone

 

[yhbae]

What is your level of ammonia and nitrite?

Also, what is the size of your tank, and what species have you had in the tank?