Hello, I kind of remember some old versions of this concept. I like the dolphin being a mean shrink (against popular belief that dolphin are docile), and the shark being a feeble old mafia boss. I don’t think the fact that the dolphin want to blame a rival boss is interesting in the economy of the logline (it’s part of his plan but doesn’t add anything really significant here – we don’t need someone to blame for a suicide). It would be more interesting to explain clearly what motivates the dolphin (does he want to become the new boss, demistifying the belief that dolphins are no leaders? Is the rival mob who push him to act like that (how)? And finally, don’t say “try to let”, maybe try to make… the problem is that the shark is depressed and ready to commit suicide than the dolphin as little to do to accomplish his goal. Maybe the comedy can emerge if despite the fact that the shark is depressed and ready to commit suicide, all attempts to push him fail. This mob fishes world can be funny and original, as a logline I feel like more work is needed.