I got wasp grouper in the 2nd level, but I couldn't keep him alive very long..and wasn't awarded it... Is it because I have to go to level 3 to get it? And what are good selling prices for the golden leaffish ???

You can get the trophy for the Magic Fish without having the necessary level of Fish Environment, but the fish has to live long enough for that to happen.

If you look at this post, you can see a pretty good suggestion for pricing your fishies!