depends on what type of community tank your talking about. my 5 inch clown took out 3 rasboras a night and now i no longer have a community tank. i now have a monster tank.
clowns are rather aggressive so try with precaution
A CK at any size would claim that whole tank as his own. They are very strong fighters. Also, the size of a CK's mouth can be very deceiving. All those fish would become feeders very quickly.
