I'm still too scared by the catfish to try again. ;_;
The only attack that could give any trouble is the tackle, and for that one you if you stay away from him he'll use the tackle instead of the jump most of the time so you just have to time your jump to dodge it (or jump early and fly away lol).
His first attack is a joke, his second you just have to stay away from him when he's underground and rush him when he's above, and his third just stay away from him and attack at a safe distance.
There's also his final attack which is hard but you don't really have to beat it (at least I didn't for Hard mode).