my tank has been massacred!!! my boyfriend and i purchased 6 juli's, 6 brevis, 6 similis, and 6 rainbow fish on thursday night. all cichlids are about 2" in size - the rainbowfish are more like 3-4".
we placed them in our new 75 gallon tank and they had been doing wonderfully. when we went to bed last night, there were no signs of any kind of trouble. we woke up this morning to a foul, skunk like smell coming from the tank - all the brevis and julis are dead and 3 similis are dead with the other 3 looking like they are on the brink. only the rainbow fish are doing fine. any ideas on what might be going on?
ammonia and nitrites are 0; Ph is 7.8, and the water temp is 78.
the fish have no signs of ick/rot/bloat/any type of identifiable disease.
my boyfriend had been checking the water parameters twice daily to monitor ammonia/nitrite spikes. ammonia and nitrite have consistently come back 0 - Ph has ranged from 7.8-8.2, water temp is 78. uncle neds was nice enough to give us some "dirty water" to help with the cycling of the tank. when we bought the rainbow fish, they were in a tank with other cichlids (i want to say ocelatus, but not sure). in any case, i highly doubt they are the culprit.
PLEASE HELP!!!