I can't make up my mind right now. I've got Bettas, African Dwarf Frogs, Clown Loaches and YoYo Loaches, and I can't tell you which one is my favorite. They all have their own particular charms that make them special. The Bettas are like dogs and come to the front of their tanks when I come in, expecting food. The ADFs are more laid-back, but they're so cute when they grab their brine shrimp or they hug the turkey baster with their front claws while waiting for the next shrimp to come close to their mouths. The YoYos are just so active and no matter what time of day, it's a certainty that I can sit down and watch them do something interesting. The Clowns live up to their name, and I get a kick out of watching them fight over a wafer, or watching them race after a YoYo (or a YoYo race after a Clown).