Unexplained Deaths

[smithyif]

Hi there just wondering if anybody can help me please , ive just checked my 100L tank and found 2 of my older platyies have died ,i know i have a few too many fish in there and have had for a few months now without any problems , my tank is 100L planted with a fluval U4 internal filter system and also a rena 600L air pump , stats for my tank are h 7.6 , nitrate approx 2.5ppm , ammonia 0 ppm and nitrite approx 0.25 ppm , any ideas or suggestions please guys

 

[mattlee]

if you are knowingly overstocked and test results show nitrite at 0.25 then this is probably your answer...... you bioload is too high for the bacteria in the filter causing a spike in nitrite