Update #2 - Leave your logic by the door, please.

It's 4:15 am and I'm still playing. Good thing it's weekend, it would suck if I had to wake up in about 4 hours due to classes.
Now I moved from trout and salmon to tuna and, in a few levels, lobsters. They heal a lot, and for non-members, it really doesn't get better than this, however, later on, I'll probably make the lobsters my main food. Now, I don't know if back then they had this, but I read on a wiki that in Karamja there's an NPC that turns all the tuna, lobsters and swordfish in your inventory into notes. This is really useful, since there are no banks in Karamja, and before I read this, I had no clue how I was actually going to make a profit with these tunas. Selling them to the general store wouldn't cut it, raw or cooked, and the run towards the nearest bank is too long and also has the cost of the boat trip, but with this NPC, you simply turn all those fish into notes, and since notes stack, you can eventually carry a ton of them back to some other place where you can either sell them raw or cook them, your choice.
The fact that you can turn a fish into a piece of paper raises a lot of eyebrows though. Just think about it.

"Na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, na, fishing!"

*wanders about*

"Why yes, I'd like to turn these 24 tunas into paper so I can then go to a bank and reclaim then, even though they'll stay here for ever and ever and ever..."