i am moving them out of my 55g, they fight every once in a while but for the most part they get along, on my 55 i have 2 aquaclear 110 filters, seems to work well, the new tank came with a fluval 304, i have pebbles in the 55, though it would be better since in the 45, they would spit the finer gravel around, and yes everything has been rearranged, almost everyday! broken glass heaters, now i have 2 metal ones. any suggestions on filtration for the 75 with 2 12" oscars, the 304 fluval probably wouldnt be enough?