just a few things to answer your question....you dont have to have a powerhead but it is good exercise for p's since they live in fast parts of streams in S.A. the powerheads create a current for them to swim in.....also i noticed you only have 2.....i would get another.....if not those two will constantly fight for territory and will do either of 2 things stress one of the fish out until they die or the fish will die just from fighting....try to make it the same size as the other two....also you are going to need to upgrade to larger tank very soon 55g or 75g.....the rbp will grow to about 5-6" in six months and then slow down after that......and like said by others no much thing as to much filtration especially when it comes to p's you should have double the filteration since they are extemely messy
