Fish

Maybe a different color can be used in the forest world than in the Icyisland.

Also, possibly there should be a few different types of fish:

Standard up-and-down movement
Curving Jump landing in a different place, going back and forth
Archer Fish
- Stays below the surface of the water, but follows tux when he is on platforms above
- Shoots high pressure water which can break blocks and knock Tux into water where the archer fish can get him
Swordfish
- Curving Jump following Tux and jumping higher when there is a chance to get Tux