Your scratchy, toothy, new mouthparts are surprisingly useful. You can either chew things up with them or, by using them more gently, pick things up. Obviously, for the moment, you are mostly just chewing, but this opens up a lot of new behaviours for you.

You’re currently hanging out in the shallows and eating whatever stays still long enough, but the land has recently been colonised by these new things called “land plants” which means there’s an awful lot of good organic waste sitting there just out of the water. If you got good at carrying all your weight on land, you could take advantage of that.