No haven't seen him puff up yet!
He is small but dangerous... I pitty the earthworm, snail... anything that he comes across.
He is already starting to recognise me and becoming quite tame. I am going to get some ghost shrimp this weekend... they can clean the tank and double up as food. What snails should I get for him to eat?
Thanks for the comments, photos taken on a Nokia 6260 and are pretty good...