Generally speaking, red fish like salmon and trout are much higher in fat and calories then white fish like cod, perch, sole, haddock etc.
That being said, DONT think that red fish is a bad option. The omega 3 fatty acids are very good for you. They will increase muscle insulin sensitivity and reduce inflammation in the body.
The key is to always look for the words 'wild caught' when purchasing seafood. Farm raised seafood is polluted fish ponds and fed corn and soy. It contains very little omega 3 fatty acids and has a very poor fatty acid profile. Wild caught fish will be caught in the ocean. Those fish will be eating everything a fish should eat - plankton, algae, little fish etc.