"Niko produces pearls that you can click on for a hefty sum of money."
Niko opens up after 34 seconds and every 40 seconds after that to reveal a pearl, which can be clicked on (not collected by pets) for $250 or in Virtual Tank, 10 shells. Niko is the only pet that does not move.
One question that always comes up when talking about Niko is: Why doesn't Niko open his mouth more often? There is a reason for this. It is because Niko thinks that opening his mouth may allow demon to steal his soul. Therefore, he keeps mouth opening to a minimum.
Niko produces an average of $6.25/sec. This is less than Shrapnel's $8.33/sec, but does not bear the risk of killing fish instead.