New fish questions!

[BMahura]

I've always loved mandarins and now that my yank only has a few fish due to a crash in my tank I'm looking at getting some new fish. I was interested in a mandarin but have herd alot of mixed opinions on keeping them. Currently I have a lawnmower blenny. Diamond goby. Pair of clowns juvenile hippo tang and a cardinal fish. I'm running a 55 gallon system. If I buy a mandarin that eats dead brine would it thrive in my tank or are the tank mates to aggressive. As well ive hers people have success in keeping copperbands in smaller tanks but is 55 to small?
Thanks guys

Brett