Bonus Pet #1: BrinkleyBrinkley is a snorkling elephant who travels around your tank. You can feed him (like your guppies) and he'll throw up money or shells.
Cost: 20,000 shells
Bonus Pet #2: Nostradamus
Nostradamus the Nose is a nose with a fin behind it. It drips snot that you can click on for money, or sometimes be eaten by guppies. He can also stop alien attacks by sneezing right before they happen!
Cost: 25,000 shells
Bonus Pet #3: StanleyStanley the Startlingly Small Sea Serpent throws balls at aliens.
Cost: 30,000 shells
Bonus Pet #4: Walter the Penguin
Walter is a penguin who, when clicked, shoots out a boxing glove 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.
He is great in combination with Vert, Brinkley, and Niko.