@Give me your fish or else..." He... never said that... I'm surprised you're angry at him when you apparently want things to be resolved with paying, and that's what they did. Also, he's being "Chaotic Neutral", that means he thinks of himself, and if it doesn't concern him, he won't go for doing good, or will he go for doing bad. He does what he wants, without caring about "good and evil" concepts. So Kaarme was right, he's being chaotic neutral. He didn't threaten them of giving him his food or dying, he said he wouldn't help for free, and they could pay him in food, which is quite different. The dangerous situation didn't arise because of him either, so it isn't evil from him to not have helped.
Good : Going to their rescue and helping them with no expectations.
Neutral : Helping in exchange for a reward or not getting involved.
Evil : Making use of their time of weakness to steal or kill them.
Plus, this is a medieval fantasy kind of world, I wouldn't get to involved and be on my guards if I were thrown into this kind of environment.