I could never find one in the world I created so I used the tutorial.
Go in, take a right then another right and there are fish in the fish.
I left out one of the ocelot so I didn't try taming both, because you need a lot of fish for this.
Basically get in the pin, do not move and then press L2 when you can tame the ocelet, which will give him fish. You will use most of the fish and it's kinda time consuming. I used 9 from the chest.