Small pet

Small pets are pets that live in aquariums or cages and can be taken out briefly for Sims to play with. They require less attention than cats, dogs, and horses, but have fewer interactions, and are not counted as household members.

The Sims
In The Sims, only one small pet was available, the fish in the Poseidon's Adventure Aquarium. Sims obviously have to feed the fish and clean the tank to ensure they remain healthy.

In Livin' Large, the guinea pig was introduced. If the cage wasn't cleaned for a long time, and it bit a Sim, the Sim would become sick. The fastest and easiest way of curing this sickness is to buy the guinea pig painting and look at it.

Many more small pets were introduced with The Sims: Unleashed. Sims were able to go to Old Town and purchase a variety of small pets, including iguanas, turtles and small birds such as budgies and love birds. All of them require feeding and cleaning occasionally, but they don't need as much attention as cats and dogs. However, unlike cats and dogs, they can - and will - eventually die, no matter how carefully they are cared for. Parrots and Cockatoos can also be bought in Buy Mode, for §939 and §749, respectively. Sims can not only feed them crackers, but also talk to them, which boosts the selected Sim's Charisma.

The Sims 2
As in The Sims, the only way Sims could have small pets in The Sims 2 base game was to have an aquarium, the Aquabox Five-Gallon Aquarium. It must be stocked by clicking on it and selecting the "Restock" options. Sims must feed the fish and clean the tank regularly, or they will die. The Sims 2: Pets added another stylish fish tank, which works the same as the base game aquarium.

In addition to dogs and cats, The Sims 2: Pets added womrats and parrots. In order to have Sims keep them, the player must buy the appropriate cage in Buy mode, then use the cage's "Restock" option to purchase the pet. This can only be done if the cage is empty and clean; womrats cost §75, while birds cost §400. The womrat cage is called the FMCU 3000 (FMCU stands for "Fuzzy Mammal Containment Unit"), while the bird cage is the Tropico Avian Sanctuary. Apartment Life, added the Modern Arf Indoor Dog Pen, which allows Sims to keep a small dog in the pen; these dogs cost §500.

When stocking a cage or pen, the player will have a choice of several fur or feather colors, and will be able to name the pet. Sims must feed small pets regularly. Womrats and birds will eventually starve if not fed, but a starving penned dog will be taken away by an Animal Control officer before it can die. Small pets that are hungry may bite, and ones that are starving will have "hungry" thought bubble above their heads. It is also important to keep the cage or pen clean, as a dirty cage not only brings down the room's Environment score, but lowers the small pet's mood, increasing the chances that it will bite. While a womrat is essentially a guinea pig, the Guinea Pig Disease from The Sims: Livin' Large does not exist in The Sims 2.

Sims can play with and watch these small pets, and can carry along the parrot or penned dog. Also, parrots can be taught to talk. Once they've learned to talk, Sims can talk to them to build Charisma skill. Sims will also build Nature enthusiasm whenever they clean the cage or talk to a bird.

Bird cages can be opened. An open bird cage will eventually let the parrot out and it will fly around the house. Nearby Sims will think this is fun. Sims cannot interact with the parrot while it's flying, and it will not escape and cannot be caught by cats or dogs.

A womrat or bird can be set free, and a penned dog can be given up for adoption.

Small pets are the only pets that young adults can keep on college lots, or that can be kept in vacation homes.

Sims can also keep collected butterflies and fireflies in a jar. If they are not released, they will eventually die and the jar will have to be cleaned. Neither the maid nor the butler will clean it, though.

The Sims 3
In The Sims 3 many aquatic animals, including fish, frogs, snails, and crocodiles, and insects can be caught and placed in an aquarium. The Sims 3: Pets feature various kinds of minor pets, which can be caught outdoors like other collectibles. Minor pets can be kept temporarily in the inventory, but they might eventually run away if kept for too long. Minor pets need to be placed in terrarium. Animals in aquariums and terrariums must be fed regularly.

Here's the list of minor pets in Pets:
 * Pet rocks
 * Birds: Blue Gold Macaw, Catalina Macaw, Cockatoo, Congo African Gray, Crow, Falcon, Spotted Sixam, Yellow Naped Amazon, Cardinal, Easter Bluebird, Gold finch, Lilac Breasted Roller, Nuthatch, Parakeet, Pigeon, Owl
 * Lizards: Anole Lizard, Ancient Dragon, Gecko, Chameleon, Pygmy Komodo Dragon, Agama Lizard, Texas Spiny Lizard, Iguana
 * Rodents: Chinchilla, Hedgehog, Squirrel, Rat, Shrew, Womrat, Chipmunk
 * Snakes: Yellow Python, Garter Snake, Emerald Tree Boa Snake, Malayan Krait Snake, Yellow Chondro Python, Scarlet King Snake, San Francisco Garter Snake, Iridescent Shieldtail Snake, Mini Python
 * Turtles: Barbour's Map Turtle, Spotted Turtle, Eastern Box Turtle, Indian Roofed Turtle, Red Eared Slider Turtle, Pygmy Tortoise, Spiny Turtle, Western Painted Turtle
 * Ant farm

In The Sims 3: Supernatural, there are some storage cabinets suitable to showcase up to 8 insects and butterflies. Additionally, Sims can store insects and butterflies from the their inventory inside the cabinets.