Looking for a small addition to a new or existing freshwater aquarium? We have the best of the small aquarium fish breeds for your tank. All of these Fish for Small Tank are less than 3 inches, but note that many of these species do best when in a small school of a minimum 3 to 5 individuals.

Before mixing new fish species, do your research thoroughly in order to make sure the environmental parameters match and they have the same compatibility. All new fish should be quarantined in a separate tank with separate equipment for 4 to 6 weeks to prevent the spread of disease.

Mickey Mouse Platy Fish for Small Tank

Platys are colorful, live-bearing fish that are very suitable for beginners. Since they are live-bearing fish, many hobbyists start out with only one fish—which can quickly multiply into many fish. The Mickey Mouse Platy is named for a very specific color pattern formed in the tail peduncle.

Other Platy species include the Red Wagtail, Wagtail, and many more.

Species Overview

Common Names: Golden moon platy, mickey mouse platy, moonfish

Scientific Name: Xiphophorus maculatus

Adult Size: 1 to 2 inches (3 1/2 to 5 centimeters)

Life Expectancy: 5 years

Guppies Fish for Small Tank

Guppies are a cornerstone of the small fish aquarium hobby. Another live-breeding species, guppy tanks are often overrun with offspring from frequent breeding. The best skill any guppy owner can learn is to tell the difference between males and females to keep populations from exploding.

Species Overview

Common Name: Guppy

Scientific Name: Poecilia reticulata

Adult Size: 2 inches

Life Expectancy: 2 to 3 years

Zebra danio (Zebrafish) Fish for Small Tank

These small, striped fish are one of the few in the aquarium hobby that don’t require tropical temperatures. Zebrafish are peaceful, community players that love schooling in groups. There are multiple Danio species available in the pet market with a variety of colors and markings.

Species Overview

Common Names: Striped danio, zebra danio, zebrafish

Scientific Name: Danio rerio

Adult Size: 2 inches

Life Expectancy: 5 years

Neon Tetra Fish for Small Tank

One of the most common small freshwater aquarium species is the Neon Tetra. These fish are known for their colorful appearance with bright red and blue stripes. They are great community fish and school together in a vibrant wave.

The Cardinal or Red Neon Tetra is another, very similar species. They are distinguishable from the more common Neon Tetra by their longer red belly bar. The Black Neon Tetra is a similar species with black bars instead of color.

Species Overview

Common Names: Neon tetra, neon fish

Scientific Name: Paracheirodon innesi

Adult Size: 1 1/2 inches (4 centimeters)

Life Expectancy: 5 years

White Cloud Mountain Minnow

The White Cloud Mountain Minnow is another species of small community fish that does not require tropical temperatures. These fish do well in temperate tanks with Zebrafish and goldfish, provided they are not snack size. These fish are common in some aquascape setups where focus is put on the plants, not necessarily the fish.

Species Overview

Common Names: Canton danio, Chinese danio, white cloud, white cloud mountain fish, white cloud mountain minnow

Scientific Name: Tanichthys micagemmae

Adult Size: 1 1/2 inches

Life Expectancy: 3 to 5 years

Harlequin Rasbora Fish for Small Tank

The Harlequin Rasbora is a small, schooling fish with a vibrant ruby coloration. These peaceful fish add a bright splash of color to planted or aquascaped tanks. There are many various species of Rasbora that stay small and do well in community tanks.

Species Overview

Common Name: Red rasbora

Scientific Name: Trigonostigma heteromorpha

Adult Size: 1 3/4 inches (4 1/2 centimeters)

Life Expectancy: 6 years

Serpae Tetra Fish for Small Tank

The Serpae Tetra is a smaller fish with a big personality. These bright red schooling fish with black fins provide color to natural tankscapes. These fish are very active, and have the habit of biting fins of their friends and tankmates.

Species Overview

Common Names: Blood characin, callistus, callistus tetra, jewel tetra, red minor tetra, red serpae, serpa tetra, serpae tetra

Scientific Name: Hyphessobrycon eques

Adult Size: 1 3/4 inches (4 1/2 centimeters)

Life Expectancy: 5 years

Panda Corydora Fish for Small Tank

The Panda Corydora is the most common corydora species seen in the pet trade. These fish have white or translucent bodies with contrasting black spots, giving them their panda-esque coloration.

There are multiple species of corydoras with similar, peaceful temperaments. The main differences between these species are their colors and markings. All corydoras are small, peaceful, bottom-dwelling, nocturnal fish species.

Species Overview

Common Names: Panda catfish, panda cory, panda corydoras

Scientific Name: Corydoras panda

Adult Size: 2 inches (5 centimeters)

Life Expectancy: 10 years

Glowlight Tetra Fish for Small Tank

The Glowlight Tetra is not to be confused with GloFish species. Their coloration comes from natural color patterns and has not been genetically engineered.

Species Overview

Common Names: Glowlight tetra, glolight, fire neon

Scientific Name: Hemigrammus erythrozonus

Adult Size: 1 1/2 inches (4 centimeters)

Life Expectancy: 5 years

Pea Puffer Fish for Small Tank

A newer addition to the aquarium hobby, the Pea Puffer is a small but mighty member of the pufferfish family. Don’t let their small size trick you! These small fish can be aggressive, even against their own kind.

The Pea Puffer is not recommended for beginner hobbyists. Proper diet and environment is key in long-term survival of these fish.

Species Overview

Common Names: Pea Puffer, Dwarf Puffer, Bumblebee Puffer, Malabar Puffer, Pygmy Puffer

Scientific Name: Carinotetraodon travancoricus

Adult Size: 1 to 1 1/2 inches

Life Expectancy: 4 years

Tiger Barb Fish for Small Tank

The Tiger Barb is an easy fish to take care of, but they do not play well in community tanks. Be sure they are in more aggressive level tanks and have lots of room to swim.

Species Overview

Common Names: Tiger barb, sumatra barb, and partbelt barb

Scientific Name:  Barbus tetrazona

Adult Size: 3 inches

Life Expectancy: 6 years

Swordtail Fish for Small Tank

Named for their elongated ventral tail fin, the Swordtail is another live bearer fish that can quickly overwhelm a small system. There are many color varieties of Swordtail available in the pet fish market.

Species Overview

Common Name: Swordtail

Scientific Name: Xiphophorus helleri

Adult Size: 3 to 4 inches

Life Expectancy: 3 to 5 years

German Blue Ram

There are many species within the Cichlid family tree, but relatively few that stay small in size. The German Blue Ram is one such species, but are not recommended for beginners given their strict water quality and habitat requirements.

Species Overview

Common Names: German Blue Ram, Ram Chiclid, German Blue

Scientific Name: Mikrogeophagus ramirezi

Adult Size: 2 to 3 inches

Life Expectancy: 2 to 3 years

Buenos Aires Tetra

The Buenos Aires Tetra is making a comeback in the aquarium hobby. Once known as voracious plant eaters, these colorful fish are being seen more in heavily planted tanks, where plant food is plentiful. These community fish are easy to care for and can tolerate many beginner mistakes.

Species Overview

Common Names: Buenos Aires tetra, diamond spot characin, red cross fish

Scientific Name: Hyphessobrycon anisitsi

Adult Size: 2 3/4 inches (7 centimeters)

Life Expectancy: 5 years

Dwarf Gourami Fish for Small Tank

Of the many gourami species, there are few that stay small. Most gouramis are medium-sized fish, but the Dwarf Gourami, as the name suggests, tops out at only 2 inches. Like other gouramis, these intermediate-level fishes have specific environmental requirements for successful lives.

Species Overview

Common Names: Dwarf gourami, flame gourami, powder blue gourami, red gourami, sunset gourami

Scientific Name: Trichogaster Ialius

Adult Size: 2 inches

Life Expectancy: 4 years

Gold (Chinese) Barb Fish for Small Tank

Although this fish is green in the wild, it has been captively bred to show brilliant golden coloration. These active fish play well in community tanks but do prefer slightly less than tropical temperatures.

Species Overview

Common Names: China barb, Chinese barb, Chinese half-striped barb, gold barb, green barb, half banded barb, half-stripes barb, Schubert’s barb, six-banded banded barb

Scientific Name: Puntius semifasciolatus

Adult Size: 3 inches (7 1/2 centimeters)

Life Expectancy: 5 years

Betta Fish for Small Tank

Betta fish are one of the most common pet fish species. Given their aggressive nature, male bettas should be kept away from other male bettas. Some female bettas can get along in groups, but not all. Betta fish come in a rainbow variety of colors and tail shapes.

Species Overview

Common Names: Betta, siamese fighting fish

Scientific Name: Betta splendens

Adult Size: 3 inches (7 centimeters)

Life Expectancy: 2 to 3 years

Hachetfish Fish for Small Tank

Looking for a more challenging and rare small fish species? Hatchetfish have a very unique, compressed body shape, known for flying over the top of the water using their wing-like fins. These fish are not for beginners, since they have very specific tank requirements.

Species Overview

Common Name: Marbled hatchetfish

Scientific Name: Carnegiella strigata

Adult Size: 1 to 1 2/5 inches

Life Expectancy: 5 years

Congo Tetra Fish for Small Tank

The Congo Tetra pushes the maximum length of the small fish category, but these schooling fish are a rainbow addition to many tanks. They are peaceful aquarium fish, with males having longer fins than females.

Species Overview

Common Name: Congo Tetra

Scientific Name: Phenacogrammus interruptus

Adult Size: 3 to 3 1/2 inches

Life Expectancy: 3 to 5 years

Beacon Fish

The Beacon fish is another member of the tetra family. Also known as the Head and Tail light tetra, this fish has distinctive copper spots that resemble lights on a vehicle. These fish do best in lower lighting with lots of plant cover.

Species Overview

Common Names: Beacon fish, beacon tetra, head and tail light tetra

Scientific Name: Hemigrammus ocellifer

Adult Size: 2 inches

Life Expectancy: 5 years

Black Phantom Tetra

Rather than bright colors, the Black Phantom Tetra is known for its darker appearance with elongated dorsal fin. These fish make a great contrast with other tetra species, who typically will all school together.

Species Overview

Common Names: Black phantom petra, phantom tetra

Scientific Name: Megalamphodus megalopterus

Adult Size: 1 3/4 inches (4 1/2 centimeters)

Life Expectancy: 5 years

Black Ruby Barb

Also known as the Purple-Headed Barb, the Black Ruby Barb has a distinct deep red coloration not commonly seen in other aquarium fishes. With a similar body shape as the Tiger Barb (above), these fish start with a pale yellow body that deepens with maturity.

Species Overview

Common Names: Purple-headed barb, purplehead barb, ruby barb, black barb

Scientific Name: Pethia nigrofasciata

Adult Size: 2 inches

Life Expectancy: 5 years

Small fish may have small bodies, but that doesn’t mean they need a small tank! Some small species have larger tank requirements due to territoriality or the need to school in groups.
Before adding any new fish to an existing tank, be sure to do your research to make sure everyone will get along and have the correct water quality requirements, including temperature.
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