My O and CK are fighting at night I think. They both like the same general area of the 240gal tank they are in, even though there are other places they could hide. The Ck is about 8" and the O is about 6-7". They are not very aggressive during the day, but both seem to have a few new scrapes (esp the ck) every other morning or so. They are the biggest two things in the tank other than a 10"RoyalPleco. Should I try to rearrange the tank to undo their territoriality, or will it gradually lessen as the CK outgrows the O? Am I doomded? I really don't want to move or get rid of either fish- The O is my 6yo son's favorite and the CK is my favorite. Any suggestions? Anyone raised this combo before? Mine have been living together for a few months with few problems until recently. They are well fed and water conditions are very good.