Anglers are hard to ID it's almost definatly of the Family Antennarius (aka frogfish) though its Genus is harder to pick out... If I HAD to guess I would say its of Genus Commerson... They can get up to 14" (that said even if its not its the biggest of the Family so worst case it wont get that big). Common name is Commerson's frogfish. I wouldn't worry about corals unless they are stinging, as you will have noticed Frogfish "perch" on rocks and sand so stinging corals are a hazard. But its interesting to see you own a Rhizotrochus since they are illegal to import, and therefore hard to find.