i have a marbled coral catshark for about 4yrs now she is 24'' and does great in 180 she is in.i was lucky in that she was already eating when i bought her.you should know that marbled coral catsharks are most nocturnail
What are the dimensions of your 180? If it's less than 4' wide, you should really consider upgrading, for the shark's sake. And to reiterate, triggers are awful mates with sharks. If you want fish in with them, check out some groupers.
Sharks need space to swim...bottom line 180 is too small for a full grown shark. People put oscars in 10g tanks and the fish live for a while doesn't mean its right or healthy for the fish so just because someone has done it before doesn't mean it will work for you or should be done. Bottom line is that person is wrong in leaving it in the 180 for its whole life.
I just watched this show on the animal planet this guy caught a near 5ft redtail catfish, saddens me that people try and keep them outright in small aquariums.
I'd stay away from a coral cat I have had a few and they are a kind of hard to keep. I sold one of them but the other two died. The first choked on a silverside and the other one wouldn't eat. I say a bamboo would be your best bet. There diffrent types and like I said before if you get a egg you'll be able to keep it in that size of for awhile. I have mine in 125gal coarl reef an she likes to hide in the cave that I made.
I've had/bred coral catsharks. I like them for size. Most bamboo sharks are 3-4 foot animals full grown, where coral cats stay smaller. Coral cats are also more active than bamboos....especially when feeding.