just to give you an idea...a have a 40g breeder where I house a 3" S. Gibbus and filtration on that are 2 marineland emperor 400s. that's 800gph on a 40 breeder...is that too much? I don't think so. there is no such thing as over filtering a piranha tank. now if you put a betta in there obviously it'll die from the current. piranha tanks need all the filtration they can get. just my 2 cents on this topic.