A regular snowflake moray will live in there as well.
Couple pieces of advice in my experience:
1) Don't focus on "filtration" as much as water flow, protein skimmers, and water changes. Especially with a FOWLR
2) Have a water making operation setup before you start. ie: Garbage can for making water, RO setup with DI, mixing pumps, etc.
3) Use RO water. The problems associated with many SW setups have to do with poor water. Algae blooms, cyano, etc. This all can come from not having a decent base water to mix your salt with. This can drive you absolutely nuts and make it very not fun.
4) As was said, quarantine. Ich in saltwater is absolutely miserable. It makes FW ich look like nothing.
5) Compatibility is huge. For a 55 I'd stick to some nice community fish: Dwarf angels, cardinals, clowns, etc.