Best Fish to Have as Pets: 10 Picks and What Each Needs

For most first-time owners the best pet fish are a betta on its own, a few fancy goldfish in a large enough tank, or a group of livebearers such as guppies or mollies. Aqueon's list of the top 10 pet fish, which ranks fish by how much personality they show, puts the betta first and the fancy goldfish second. What makes a fish a good pet is less the species than matching it to the tank you can give it, and letting the tank mature before the fish go in.

The list and care notes are from Aqueon's top 10 pet fish.

• Betta: the fish most often given a name. Males are fiercely territorial, so keep one alone; they prefer 78 to 82°F and need a heater in cool homes. See betta fish.
• Fancy goldfish: easy to care for and engaging, but they grow large; a 10-gallon tank works only while young. See goldfish types.
• Mbuna cichlids: 2 to 8 inches, active, aggressive to non-cichlids; they need harder, alkaline water. See mbuna.
• Convict cichlids: small, feisty, breed easily and defend their young.
• Ocellaris clownfish: most are captive-bred now, but they need a marine setup. See ocellaris clownfish.
• Oscars: over 12 inches; a 75-gallon minimum and 125 gallons recommended. See oscar.
• Tiger barbs: best in small groups; may nip the fins of slower fish.
• Mollies: active and social; they eat algae and herbivore foods.
• Fancy guppies: constantly active, bred in the hobby for over 100 years. See guppies.
• Freshwater angelfish: cichlids, 3 to 4 inches across the body and over a foot tall with fins. See freshwater angelfish.

Start from the space and work backwards:

• Desktop or small tank: one betta (Aqueon), or small community fish; see small aquarium fish for what fits 3, 5 and 10 gallons.
• Community tank: a group of guppies, platies or mollies, tetras or zebra danios; each page gives the tank size. See tetras, platies and zebra danio.
• Goldfish: Wikipedia gives about 20 gallons for each common or comet goldfish and about 10 gallons for each smaller fantail, and says fishbowls are bad for goldfish health.
• 75 gallons and up: an oscar (Aqueon), or larger cichlids.
• Saltwater: clownfish are on Aqueon's list, but they need a specialised marine setup.

No fish is truly low maintenance, but some ask for less. Of Aqueon's top 10, the small fish that need no special water or tank, such as a single betta, guppies and mollies, are the simplest; oscars (75 gallons or more), mbuna (harder, alkaline water) and clownfish (a marine setup) ask for much more. What actually makes any tank easy is doing the setup right:

• Cycle the tank first. Aqueon says the nitrogen cycle typically takes three to eight weeks: ammonia rises first, nitrite by the second week, and the tank is cycled when ammonia and nitrite read zero and nitrate is being produced.
• Add fish slowly. Aqueon warns that stocking a new tank fully at once causes 'New Tank Syndrome', where ammonia and nitrite climb to unsafe levels.
• Test and change water. Until the cycle is established, Aqueon suggests testing ammonia and nitrite every two to three days and changing 10 to 25% of the water every few days.

Our freshwater fish tank guide walks through the setup.

PetSmart's fish compatibility guide sorts fish into groups and flags the risky pairs:

• Bettas get along with many schooling and small fish, but not with angelfish, cichlids or freshwater 'sharks'.
• Goldfish and koi are best kept only with other goldfish or koi, plus large plecos.
• African and South or Central American cichlids are mostly kept in species-only or closely watched tanks.
• Semi-aquatic crabs are not compatible with nearly any fish.
• Size rule: larger fish may eat a smaller tank mate.

PetSmart also notes that individual fish vary, so watch any new group closely for the first days.

The fish usually meant is the Asian arowana. The Hustle reports typical prices of $1,200 to $5,500, an average farm sale of about $3,000, and a purportedly $300,000 sale of an albino fish. Wikipedia says hobbyists may pay thousands of dollars for one.

It is not a pet option in the United States. Wikipedia says the Asian arowana was placed on CITES Appendix I, the most restrictive category, in 1975, and is listed under the US Endangered Species Act, so it cannot be kept there without a permit. See our Asian arowana page. For expensive fish you can legally keep, see koi prices.

Check the adult size and the tank each fish needs on its species page, confirm it is legal where you live, and never release an unwanted pet fish into the wild; released goldfish become invasive pests in North America and Australia (Wikipedia). If you are not sure what a shop fish is, a photo with FishLens gives the species name, so you can look up its adult size before it goes home.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Every number names the organisation it comes from, and where sources disagree we say so instead of picking one silently. Prices and rules are given with the date we checked them; they change, so confirm before you rely on them. If you find an error, tell us and we will correct it.