Guppim Family

A pure Water-Type evolution line for Pokemon Copper/Zinc/Iron.

The Coin Pokemon, Guppium
The Star Pokemon, Fishstar
The Diamond Pokemon, Kinguppy

Using a Star Potion on a Guppium evolves it into a Fishstar.
Level Up a Fishstar while it's holding a King's Rock to get a Kinguppy

They all have an ability called Jackpot, which doubles money from battles!

Guppium can learn Pay Day as an Egg Move!
Fishstar learns Swift.
Kinguppy learns Power Gem.