Fishing Revamp, fish tanks, and more aquatic related things.

I love collecting mobs, especially the animals. However, squid and dolphins are nearly impossible to keep around, which sucks. And with fish, it would be nice to have a fish tank block so you could bucket the fish and put them in there. 

Lots of game mechanics have been improved, but fishing really hasn't aside from adding fish as mobs. Most players don't want to fish, and I think it would be nice to make fishing more fun. Lots of other games have found ways to make fishing fun, and it would be cool for that to be the case in Minecraft. 

Also, having more varieties of fish would be cool, but this is coming from someone who also just really likes fish... and birds.