Well we just picked up a 1.5yr established 20 gallon tall reef tank. We have some anthelias, and zoas along with 1 clown, 5 snails, and 5 hermits. We are deciding what fish to get next. We like mandarin dragonets, maybe a chromis, but would like a good fish to swim around with the clown. And I pretty much limited to 3 small fish? I don't want too heavy of a bio-load, and plan to fill it with some corals. Plus something to keep the sand bed shifted..