depends on whta your into i personally have had bad luck with aros but i loe my ck's they never cease to amaze me once i went away for awhile and had someone looking after my fish but they didnt do any maitenance plus one of my filter shut down and i pissed when i returned my water was almost brown but there were my ck's looking at me like everything was fine i couldn't believe how well they were doing given the water quality