Fishing around Tromsø can be relatively easy. If you go fishing at the right time and place, you can catch a fish with nearly every throw. The sea is practically boiling with fish! The fish you can get include pollock and cod (sei og torsk). To get a cod, the thing to do seems to be to let the lure sink deeper. Pollock is easier to get. There are so many of them that sometimes the hook will be caught on their body. Both fish can be caught easily with spoon lures of the cheapest and second cheapest kind.
One good place to go fishing in Tromsø is Hella. I haven't really figured out what is the right time of day to go, but typically a good time seems to be the time between low tide and high tide. Here's a map of the place: