You should make sure it does well in marine salinity for its full lifespan. If so, I don't see any reason it would be a problem. Looks like a scorpionfish-type shape, so it should be reef-safe, as it won't be inclined to pick at corals. It's not like the lil guy will be looking around going "what's up with this??? I don't like this new stuff".
Fish don't care what their environment looks like, as long as they have hiding places. You could set up a reef tank with pink castle decorations, and as long as there was enough live rock for the biofilter, everything would happily live in and on the pink castles.