The Peo is an Aquatic Petpet. They look a lot like seahorses. They are available from the Shop Wizard, or Trading Post starting from around 43,000 NP for an Orange one. The Peo can be painted Blue, Christmas, Faerie, Green, Island, Mutant, Orange, Plushie, Red, and Yellow.
Peos are very pretty, but don't they know it. They are very demanding and have temper tantrums if they don't get what they want.