I likey.

this is really brilliant for a first, but I'd advise getting non-royalty free music and stop using comic sans.

nice art!

Technically speaking your animation is rather good for it being your first.
the premise can work.
My biggest Point of Criticism is that it is really uninteresting to watch.
it all takes place from the same camera position and the way the fish Die should be a little more varied for the purpose of keeping the viewer on there toes. this would also help your message as it would enforce the notion that death can happen anytime anywhere.

Try having more dynamic camera angles or at the very least change the camera a little bit. i know this is difficult to do in 2d animation but thats really no excuse not to try.

for example after the first fish got eaten maybe you could subvert the viewers expectation by having the fish Die in a way that contrasts that.
The scene might play out in the second one as he gets rejected he starts looking around in panic for a fish to come in an eat him but then an anchor falls on him slicing him in half or simply crushing him on the sea floor..

Get creative with it. Animation is a fun medium. Allow it to be fun.

Anyway Best of luck! Continue to work on what you love!