Fish A–Z

12 Popular Aquarium Fish, With Pictures

Freshwater and marine favourites — what they look like and what they need

Betta

Freshwater · 6-7 cm · Semi-aggressive

Labyrinth fish from Thailand; males flare vivid fins and must be kept alone.

Photo: Nippyfish · CC BY 2.0

Guppy

Freshwater · 3-6 cm · Community

Hardy livebearer; males show colorful tails and they breed readily in aquariums.

Photo: Holger Krisp · CC BY 3.0

Neon Tetra

Freshwater · 3-4 cm · Community

Tiny Amazon fish with a glowing blue-and-red stripe; best kept in schools.

Photo: Holger Krisp · CC BY 3.0

Angelfish

Freshwater · up to 15 cm · Semi-aggressive

Tall, triangular South American cichlid from the Amazon; peaceful but territorial when breeding.

Photo: Rjcastillo · CC BY 4.0

Goldfish

Freshwater · 15-30 cm · Peaceful

Domesticated East Asian carp kept for centuries; can outgrow small bowls considerably.

Photo: James St. John · CC BY 2.0

Molly

Freshwater · 6-12 cm · Community

Adaptable livebearer tolerating fresh and brackish water; popular black and orange varieties.

Photo: Hugo Torres · CC BY 2.5 es

Discus

Freshwater · 15-20 cm · Peaceful

Round, disc-shaped Amazon cichlid prized by hobbyists but sensitive to water quality.

Photo: Doronenko · CC BY 3.0

Oscar

Freshwater · 25-35 cm · Aggressive

Large, intelligent South American cichlid that recognizes owners and needs a big tank.

Photo: Jón Helgi Jónsson ( Amything ) · CC BY-SA 3.0

Clownfish

Marine · 8-11 cm · Semi-aggressive

Orange-and-white reef fish that shelters unharmed among the stinging tentacles of sea anemones.

Photo: Nick Hobgood · CC BY-SA 3.0

Blue Tang

Marine · 25-30 cm · Semi-aggressive

Bright blue reef surgeonfish with a scalpel-like spine near its yellow tail.

Photo: Holger Krisp · CC BY 3.0

Mandarinfish

Marine · 6-8 cm · Peaceful

Small, vividly patterned reef dragonet from the Pacific; famously hard to feed.

Photo: Luc Viatour · CC BY-SA 3.0

Koi

Freshwater · 60-90 cm · Peaceful

Ornamental carp bred in Japan for pond keeping; can live for decades.

Photo: Eistreter · CC BY-SA 3.0

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Freshwater and marine favourites — what they look like and what they need — browse the full picture A–Z, search any name, and see care notes for the popular fish.

See all 1,300+ fish, A–Z