From Fish Hooks Wiki
Raccoons like eating cattlefish, and often grab them from the tanks when there's not a bodyguard (ie. a snake) there. Cattlefish sometime go astray. Also, cattlefish like (pity) chocolate and when cattlefish see a cat, they swim away. This happened once, and the cattlefish piled together and ended up breaking the tank. Eventually, there were brought back into the tanks, with a little help from Milo's tears.
This is a list of names that Milo gave cattlefish, in order: