Is the stonefish he is keeping a Synanceia horrida, these guys are definitely the worst stonefish to keep. They produce a lot of waste, are the most still of any stonefish (they actually do not even go out with the tide but rather sit there and get expossed with air), resemble a rock the most and are the most venomous fish in the ocean. They honestly are not a fish to keep, i dont understand why people keep these, there basically a rock that eats! Good thing is it would be vey hard to get stung, they have flesh over there spine that needs to be pushed back with pressure in order to inject into something.
A funny story, a few years ago i was up in north queensland with my family and we decided to go look at the rockpools. After a few hours of looking we started to walk back to the car, i took one of my boots of and took one last step and my booted foot went directly on a stonefish, i took my boot of to check if it had got me at all, but the spine did not quite get through my boot, i was verry lucky.
Probably wasn't the funniest story ever, I guess!