He may be mis-ID'd. All along we've been deciding between a pictus and a maculatus. Then we found a couple of references online to the ones with the 3 tail spots were the pictus'. Now I see in Scott Michael's Reef Fishes book he has it ID'd as a maculatus.
Now, I wouldn't be inclined to believe one above the other, but Scott Michael's as an age progression and this little 3 tail spot angler does indeed turn into a warty. It doesn't make a difference either way... they will be about the same size.
Anglers can be mixed with other fish as long as they are larger than the angler and won't be picked Mr. Froggy. Sometimes they still try to eat the larger ones.