If you like canned tuna then you might like canned mackerel (but don't get the one in oil - I always make that mistake), it's packed with omega 3 so it's really good for you.
No fish should truly taste or smell "fishy" if it does it's not fresh so always sourcing good fresh fish is the key. White fish is generally very light in flavour so things like cod, haddock, coley and pollock are good if you want something that has an easily hidden flavour. I tend to eat lots of salmon and sea bass bit lots of people find the taste a bit fatty. Swordfish and shark are good too, much less like fish and more like a meat.
Also don't rule out seafood, it's been a real lifesaver for me when low-carbing because it's easy. Tiger prawns make a great snack and if you feel adventurous there is a whole array of different seafood you can have. Good low fat source of protein.
My favourite way of cooking good fish is just to seal it up in some foil with a squeeze of lemon, maybe a drop of white wine, and steam it until cooked (usually 20 minutes or so depending on the thickness).
A little note on tuna though, it has been said you shouldn't consume more than 2 cans a week due to trace heavy metal deposits, particularly if you are or are planning to get pregnant.
Good luck with your fishy journey