Cool game, love the clean art. Gameplay is pretty fun for being so simple, controls feel good. I'm assuming "Click or hold" is supposed to be "Click and hold" in the description -- I tried only clicking but it didn't move me much.
Making some of the fish act as hooks was kind of odd. It makes picking up the fish just another thing to avoid rather than a possible energy option.
The biggest thing missing is sound. Some underwater ambience would add a lot to this. You could also have sounds for the bubbles, a "splash" sound for the hooks entering the water, a "reel in" sound when the fish is caught... lots of possibilities there.
As far as polish goes, you could add in some background kelp/rocks/etc to make the background look a little less flat. You could add a "splash" particle effect for the hooks entering the water.
Also, just a small thought, but you could have the "bread crumbs" move to their positions and then slowly fall to the bottom. You'd have to make the hooks able to reach the bottom at that point so that the player can't just sit on the bottom and wait for crumbs, though.