which makes more money per hour?

 

- making cannonballs from steel bars

 

- fishing rocktail

 

i am 99 fishing

Grimy's Spreadsheets say that making cannonballs is 190k/hour. And at a price of 2k per rocktail and 400 gp per bait, you need to catch ~120 rocktails per hour for the methods to be equal. Any more, and it's better to fish, and less and cannonballs is better.

Rocktails are somewhere in the 250k gp/hr range.

Rocktails, and they give you pretty good xp (third to barbarian heavy rod and fly fishing) unlike cannonballs which are terrible.

The only reason you ever would want to cannonballs is to pay absolutely no attention to the game for 3 minutes at a time, but still get something done.