Check out this interesting project by Clayton Boyer and Forrest Burrnett featured in Scroll Saw Woodworking & Crafts issue 51, due out the summer of 2013.
Not only are these gears shaped like fish, but they have a very interesting intermittent motion. When the drive gear makes a revolution, it spins each of the smaller gears just one turn in sequence. The smaller gears remain stationary during the remainder of the cycle.
[ Thanks Charles! ]