[Reefcherie]

Rule of thumb: never keep any fish w/ an angler that isn't at least 2x its present size. They have been known to attempt to eat other fish up to that point (even those with spines!). Unfortunately, such an encounter is generally fatal to both the angler and the other fish. The angler's digestive system is very slow and eating too large a meal can prove toxic to it.

Scott Michael, in Reef Fishes Vol. 1, lists these fish as most likely to harm frogfishes: Batfishes, Angelfishes*, Butterflyfishes*, Surgeonfishes, Triggerfishes*, Flefishes, Trunkfishes, Pufferfishes and Porcupinefishes. Those w/ the "*" denotation - "The species in these families that eat zooplankton are of little to no threat to frogfishes." He also mentions that herbivores like Rabbitfishes and Blennies are also potential frogfish nippers.

He lists potential tankmates as: Soldierfishes, Squirrelfishes, Scorpionfishes*, Groupers*, larger Hawkfishes*, Snappers*, Grunts and Sweetlips, Swalllowtail Angelfishes, Pyramid Butterflyfishes, Monos. The "*" fishes may eat a frogfish that can be swallowed whole.

Most people find that the safest thing to do is to keep frogfishes in species-specific tanks.