Tadpoles should spawn naturally in swamps, and they should move around a little more. Right now they do not spawn naturally, and their move speed is so low they seem to stay in place while constantly trying to swim.

There's no point to them spawning naturally as they'll just grow up into toads.

They will move around if they have enough space, but their fairly low speed in intended.

Baby animals of other sorts spawn naturally. But I can implement that on my end anyways =]