Capricorn + Aquarius + Pisces

Capricorn (Houndour+Corsola): They stay away from the sun above and feed on seaweed during the day. When night falls, many go to the surface to make frightening noises which scares away fishermen and swimmers who hear it.
 
Aquarius (Slowbro+Spoink): Its shallow head contains a unique kind of mineral water that give it power. If all the water falls out he is defeated (although it's not easy to do). It lives in swamps and waits for challengers to pass by.
Design based on the Kappa
 
Pisces (Forretress+Remoraid): A probe can be launched from this Pokemon to do different tasks. It is water resistant due to its steel components and its brain is a super computer. The best way to defeat it is to confuse it.
Pisces is my symbol