I'd stick with the BTA for the dragonet's sake. As well as being hardy, they're also the least aggressive (shorter tenticles). I'm going to assume you have a mandarin, and since they live on the rocks they can easily hop into a nem by accident and get swalloed up because they're slow swimmers. If your maroons are THAT small, I think it would give the nem some time to toughen up and get used to the tank before they decide to beat it up. lol