Pet stores can offer a wide variety of fish depending on the store’s size and customer base. Most pet stores will offer fish suitable for aquariums and fish bowls. Larger stores or specialty shops will also offer saltwater species and larger fish for ponds. When buying fish, important considerations are life expectancy and fish compatibility. You also want to know the types of environments and the amount of space your fish will need to thrive.
Siamese “fighting fish” and betta fish stay small, move slowly, and don’t typically care for long journeys, which can make them ideal for fish bowls. White clouds are approximately one inch long and also well-tempered for fish bowls, and they fare best in groups of six or more. Guppies are common bowl fish but some won’t get along with each other in confined spaces. They live best in larger groups: Three males and twice as many females is a healthy group. Goldfish are often selected for “goldfish bowls” because they are durable -- but they're not ideally suited for confined spaces. Goldfish can grow fast when they are healthy, and a bowl that's too small will stunt their growth.
Rainbow fish are popular for aquariums because they are colorful and can be relatively inexpensive. Tiger, green, cherry, gold, rosy and tinfoil barbs average one and a half to three inches and can also thrive in aquarium environments. Tetras are vibrant with color and available in a variety of shapes and sizes; neon tetras, black skirts, serpae tetra and silver tip tetra are common in pet stores. Most pet stores will also carry mollies and danios which are approximately one to two and a half inches long. Many aquarium owners want at least one plecostomus catfish; these fish feed on the algae in a tank and keep the water clean.
One of the most popular fish for saltwater aquariums is the clownfish, which is hardy and strikingly colored. Lionfish, alternatively known as “fire fish” and “scorpion fish” are also well known for their interesting and complex look. Putterfish are thought by some to be the best saltwater “pets” because they can live a long life and are fairly expressive. The great majority of sharks are not well-suited for confined spaces, but for those aquarists who must have one for their large aquariums, banded and coral cat sharks, reef sharks and marbled bamboo sharks can be found in some specialty shops. Rays should only be purchased by advanced aquarists because they have particular environmental needs and some can sting and cause injury. Other popular saltwater fish that can be found in large pet stores and specialty shops include sea horses, angelfish, gobies, small grouper, damsels, dartfish, dragon nets, butterfly fish, frog fish, batfish and antithies.
Popular pond fish are koi, goldfish and banded hi-fin shark. Koi are available in a range of shapes and sizes. They are typically bought when they are three to four and a half inches, and they can grow to 16 inches or more depending on their species and environment. Solid black koi, gold ogon koi, platinum ogon koi, butterfly koi, kohaku koi and kikusui koi are some of the types that may be available in larger pet stores and specialty shops. Banded hi-fin shark can grow to be 15 inches long and can live with goldfish and koi.