Here's a full list of the fish, aliens, and pets to the game. Please note that due to stories being a large part in a pet or alien's characterization, all story-related spoilers will be unmarked.
- Real Men Eat Meat: They're bigger than guppies, and they're pretty fierce looking.
- One-Gender Race: Considering they create living creatures, they're likely all female. Either that, or they turn the guppies they eat into beetles.
- Explosive Breeder: They create guppies at a really fast rate. Especially noticable when you have a lot of breeders.
- One-Gender Race: Considering they give birth, they are almost certainly Always Female. Still possible for it to be otherwise, though.
- Suspiciously Similar Substitute: They give birth, they have a large belly, and they have a guppy color scheme. Yep, it's the fish version of Prego.
- Berserk Button: He gets an angry face when an alien is in the tank. Considering what they did to him, can you honestly blame him?
- Beware the Nice Ones: He left gash for dead one time.
- Roaring Rampage of Revenge: An alien ate his friends, and he's trying to return the favor.
- We Used to Be Friends: He used to be besties with Gash, until he left the latter for dead.
- Crutch Character: He's pretty helpful early on for growing fish, but falls out of use when level 3 food is available.
- The Dutiful Son: His main reason for working around the tank is because he needs money for his mother's hospital bill.
- Creepy Good / Dark Is Not Evil: His codex entry states that people avoid using him because they fear that, him being a product of occult forces, will turn on them. The codex states that he obviously isn't evil because he would drop rat poison if he was.
- Crutch Character: He is good for starting in earlier levels where fish are still young and are either incapable of laying coins or can only provide coins worth $15 at a time, but he soon gets outclassed later on when you have multiple fish dropping coins or diamonds at a time.
- Dem Bones: He is a skeleton fish.
- Perpetual-Motion Monster: His main selling point is that he can provide money without the need to eat.
- A Wolf in Sheep's Clothing: Is accused of making it easier for aliens to kill fish, since he wrangles them all into one spot. While this can happen, especially against Type-U, he more often than not protects the fish.
- Alluring Anglerfish: He's unlike other examples since he lures fish away from danger.
- Animal Gender-Bender: His model is that of a female angler fish as males are much smaller to the point that they attach to females for life as a reproductive organ.
- Back from the Dead: Her main capability is to revive fish that have been killed without being eaten, such as those killed by starvation, by rockets, or energy orbs.
- Gameplay and Story Segregation: After the fifth tank, she revives pets that have been eaten, despite being unable to do so normally.
- Holy Halo: Befitting her angelic theme, she has a halo that periodically vanishes and reappears.
- Non-Action Guy: Is notably absent during the final battle.
- Healing Factor: Whenever he enters his blue mode, the energy from your lasers get absorbed and converted back into health.
- Improbable Weapon User: Uses a butcher's knife, a broken pitchfork, and a flyswatter.
- Stalker with a Crush: His name is actually what his ex-girlfriend calls him because he would act like it never happened and would constantly call her and wait outside her door.
- Shout-Out: He uses the T-Rex screams from Jurassic Park when he enters and when he switches off his healing mode.