After you have completed Adventure Mode the first time, Bonus Pets become available for purchase. You purchase them with Shells from your Virtual Tank, Time Trial Mode or Challenge Mode.
Bonus Pet #1: Brinkley[]
See Full Article: Brinkley
Brinkley is a snorkling elephant who travels around your Tank. You can feed him (like your Guppies) and he'll throw up Money or Shells, depending on the game mode.
Cost: 20,000 Shells
Bonus Pet #2: Nostradamus[]
See Full Article: Nostradamus
Nostradamus the Nose is a nose-shaped fish. It drops snot that you can click on for 1$ or 1 Shell, and it can eaten by Guppies, which will turn the Guppy itself into another Nostradamus. He can also stop Alien attacks by sneezing right before they happen.
Cost: 25,000 Shells
Bonus Pet #3: Stanley[]
See Full Article: Stanley
Stanley the Startlingly Small Sea Serpent throws balls at Aliens and their projectiles.
Cost: 30,000 Shells
Bonus Pet #4: Walter[]
See Full Article: Walter
Walter the Penguin shoots out a boxing glove when clicked on, which does the following:
1. If the object that is punched is a pet, it will make the pet perform its ability.
2. If it's a Breeder, it will create a baby guppy. Note that this does not work in Virtual Tank.
3. If it's a fish, it will produce money.
Costs: 35,000 shells
He is great in combination with Vert, Brinkley, and other money-producing Pets.