its a juvenile sargassum angler (histrio histrio), a frogfish, one of the few lureless anglers.
They come in every year in droves attached to free floating sargassum that migrates to the gulf every spring
Anyway, these guys get pretty good size and grow quickly. They are extremely aggressive feeders, and if you haven't noticed yet it will attempt to eat pretty much every tankmate including similar sized sargassum anglers