hi,
i've got a bangii cardinal n it seems quite peaceful. it doesn't harass my other fish... however, they onli eat meaty stuff for their diet, so u can't feed them wif pellets or any vege kinda food...
i read sumwhere dat they dun really mix well wif the same kind. i mite be wrong so can any experts out there clarify this???
sorry, no exp wif urchins...
hope i was sum help