I have a green spotted puffer (yes, he's SW
as an adult) in a 40 gallon with lots of macro algae 20lbs of live rock, a HOB
refugium that adds 5 gallons water volume, a skimmer, and an Aquaclear 500. He's a four inch fish that seems to be finished growing (growth was rapid for six months but no growth the last six months) so I think I could put another fish or so in with him space wise. Inverts are out of the question, they would be snacks.
He's accidentally nipped me before while I was feeding him and while he makes short work of ramshorn snails and ghost shrimp it doesn't more than pinch my skin. I know human skin is quite tough but I thought it'd give you an idea of what his bite is like. His mouth can take in snails smaller than a quarter inch.
There are plenty of holes in the live rock he can't get into and the macro provides pretty good cover.
Any ideas what I could put in with him? Preferably something either colorful or with an interesting personality.