Niko is earned on level 1-2, and opens up every once in awhile to reveal a Pearl, which can be clicked on for $250. In the Virtual Tank, Niko's pearl is worth 10 shells, and opens once every 40 seconds. Well, not much rarer than a Beetlemuncher's pearl because it's worth $500, but she's much prettier than Shrapnel.
He is not very useful once shrapnel comes along because shrapnels bombs are the same value but he drops them more often. On the other hand though, Niko does not kill the fish with his pearls in any way shape or form. Shrapnels bombs will kill fish on impact.
Anti-Niko is an alien clam who first appears in insaniqualien. He is as powerful as anti-stinky.
Niko doesn't open his mouth very often, because he is afraid that opening his mouth will let demons steal his soul.