Dead Fish

[Natescuba]

I have had a 5 gallon fluval spec V (5 gallon) FW non-planted tank going for about 5 months, however when I did my last cleaning( remove decor, clean gravel) my 4 tetras died, however my black mollies are fine, what could cause this.

P.S. I know it was overstocked, but I was planning on giving away the mollies anyway.

thanks

 

[Peteostler43614]

What are your levels? Sometimes in small tanks when you gravel vac you stir up loss of junk and the ammonia spikes.

 

[absolutangel04]

How often do you clean it? Did you test the water parameters before cleaning?