Aggressive angel fish and nitrites...

[kazzael]

We set up our 55 liter tank about 2.5 months ago and gradually introduced 6 red platy, 6 blue neon, and 2 ghost shrimps. They all recovered from Ich and recently we introduced 3 small angel fish and a small Borneo sucker. The three angel fish seem to be acting very aggressively towards all the other fish in the tank. We noticed that the ghost shrimps, which are usually swimming around happily in the tank, had not been coming out of their shelter for about 4 days. Yesterday evening we found one of them dead at the bottom of the tank.

The other issue we seem to have is that we can’t get the nitrites down. Ammonia is zero. We know that the final solution is to introduce a more advanced filtering system (now sponge filter)…

Any advice regarding the apparently not so angelic angel fish and nitrites is most welcomed!

 

[misterking]

Well first of all your tank is MASSIVELY overstocked, that is a ridiculous amount of fish for only 55 litres. Did you cycle the tank?

Angelfish shouldn't be in less than a 30gallon tank per pair. They should also be kept in even-numbered groups. Sooner or later one will be singled out and as small as your tank is bullied to the point of exhaustion/death. Aggression increases in an unsuitable environment. They're also naturally predatory cichlids, hence the aggression and your other fish hiding.

You unfortunately only have space for the 6 tetras, shrimp and borneo sucker in there.. I suggest taking the rest back and doing a fish-in cycle. If you want that many fish, I'd recommend at least a 55 GALLON (250 litres) rather than 55 litres so you can comfortably keep 4 angelfish and the rest of your fish with little/no aggression.