Best Fish for a 20 Gallon Tank
Twenty gallons opens up most of the classic community fish: tetras and rasboras in proper schools, corydoras groups, dwarf gouramis, and the first larger centrepiece fish. The long twenty-gallon footprint suits active swimmers far better than the tall one.
96 species · ordered by how many Shoal & Stem keepers have them · every card links to a full care guide
Otocinclus
Otocinclus vittatus
10 gal min · 1.5" adult · Peaceful
Pygmy Corydoras
Corydoras pygmaeus
10 gal min · 1" adult · Peaceful
Celestial Pearl Danio
Danio margaritatus
10 gal min · 1" adult · Peaceful
Guppy
Poecilia reticulata
10 gal min · 2" adult · Peaceful
Halfmoon Betta
Betta splendens 'Halfmoon'
5 gal min · 2.5" adult · Semi-aggressive
Ember Tetra
Hyphessobrycon amandae
10 gal min · 0.8" adult · Peaceful
Julii Corydoras
Corydoras julii
15 gal min · 2.5" adult · Peaceful
Neon Tetra
Paracheirodon innesi
10 gal min · 1.5" adult · Peaceful
Panda Corydoras
Corydoras panda
15 gal min · 2" adult · Peaceful
Fancy Guppy
Poecilia reticulata
10 gal min · 2" adult · Peaceful
Honey Gourami
Trichogaster chuna
10 gal min · 2" adult · Peaceful
Cherry Barb
Puntius titteya
15 gal min · 2" adult · Peaceful
Kuhli Loach
Pangio kuhlii
20 gal min · 4" adult · Peaceful
Black Neon Tetra
Hyphessobrycon herbertaxelrodi
10 gal min · 1.5" adult · Peaceful
Endler's Livebearer
Poecilia wingei
10 gal min · 1.5" adult · Peaceful
Harlequin Rasbora
Trigonostigma heteromorpha
10 gal min · 2" adult · Peaceful
Peaceful Betta
Betta imbellis
10 gal min · 2.5" adult · Peaceful
Platy
Xiphophorus maculatus
10 gal min · 2.5" adult · Peaceful
Bristlenose Pleco
Ancistrus sp.
20 gal min · 5" adult · Peaceful
Bronze Corydoras
Corydoras aeneus
20 gal min · 2.75" adult · Peaceful
Peppered Corydoras
Corydoras paleatus
20 gal min · 2.75" adult · Peaceful
Plakat Betta
Betta splendens 'Plakat'
5 gal min · 2.5" adult · Semi-aggressive
White Cloud Mountain Minnow
Tanichthys albonubes
10 gal min · 1.5" adult · Peaceful
Albino Corydoras
Corydoras aeneus
15 gal min · 2.5" adult · Peaceful
Clown Pleco
Panaque maccus
20 gal min · 3.5" adult · Peaceful
False Julii Corydoras
Corydoras trilineatus
15 gal min · 2.5" adult · Peaceful
Betta
Betta splendens
5 gal min · 2.5" adult · Semi-aggressive
Bolivian Ram
Mikrogeophagus altispinosus
20 gal min · 3.5" adult · Peaceful
Cardinal Tetra
Paracheirodon axelrodi
15 gal min · 2" adult · Peaceful
Clown Killifish
Epiplatys annulatus
5 gal min · 1.5" adult · Peaceful
Emerald Dwarf Rasbora
Danio erythromicron
10 gal min · 1" adult · Peaceful
Galaxy Koi Betta
Betta splendens 'Galaxy Koi'
5 gal min · 2.5" adult · Semi-aggressive
Green Neon Tetra
Paracheirodon simulans
10 gal min · 1" adult · Peaceful
Hillstream Loach
Sewellia lineolata
20 gal min · 2.5" adult · Peaceful
Powder Blue Dwarf Gourami
Trichogaster lalius
15 gal min · 3.5" adult · Semi-aggressive
Rummy Nose Tetra
Hemigrammus rhodostomus
15 gal min · 2" adult · Peaceful
Salt & Pepper Corydoras
Corydoras habrosus
10 gal min · 1.5" adult · Peaceful
Swordtail
Xiphophorus hellerii
20 gal min · 4" adult · Peaceful
Zebra Danio
Danio rerio
10 gal min · 2" adult · Peaceful
Albino Bristlenose Pleco
Ancistrus sp.
20 gal min · 5" adult · Peaceful
Chili Rasbora
Boraras brigittae
5 gal min · 0.8" adult · Peaceful
Crowntail Betta
Betta splendens 'Crowntail'
5 gal min · 2.5" adult · Semi-aggressive
Delta Betta
Betta splendens
5 gal min · 3" adult · Semi-aggressive
German Blue Ram
Mikrogeophagus ramirezi
20 gal min · 3" adult · Peaceful
Green Corydoras
Corydoras aeneus
15 gal min · 2.5" adult · Peaceful
Kerri Tetra
Inpaichthys kerri
10 gal min · 1.2" adult · Peaceful
Molly
Poecilia sphenops
15 gal min · 3" adult · Peaceful
Tiger Barb
Puntigrus tetrazona
20 gal min · 3" adult · Semi-aggressive
Veiltail Betta
Betta splendens
5 gal min · 3" adult · Semi-aggressive
Apistogramma Borellii
Apistogramma borellii
20 gal min · 3" adult · Semi-aggressive
Cobra Guppy
Poecilia reticulata
10 gal min · 2" adult · Peaceful
Dalmatian Molly
Poecilia sphenops
20 gal min · 3" adult · Peaceful
Double Tail Betta
Betta splendens 'Double Tail'
5 gal min · 2.5" adult · Semi-aggressive
Dwarf Gourami
Trichogaster lalius
15 gal min · 3.5" adult · Semi-aggressive
Emerald Corydoras
Brochis splendens
20 gal min · 3" adult · Peaceful
Glowlight Tetra
Hemigrammus erythrozonus
10 gal min · 1.5" adult · Peaceful
Gold Barb
Barbodes semifasciolatus
20 gal min · 3" adult · Peaceful
Gold Dust Molly
Poecilia sphenops
20 gal min · 3" adult · Peaceful
Lambchop Rasbora
Trigonostigma espei
10 gal min · 1.75" adult · Peaceful
Lemon Tetra
Hyphessobrycon pulchripinnis
10 gal min · 1.5" adult · Peaceful
Red Swordtail
Xiphophorus hellerii
20 gal min · 4.5" adult · Peaceful
Silvertip Tetra
Hasemania nana
10 gal min · 1.5" adult · Semi-aggressive
Sparkling Gourami
Trichopsis pumila
10 gal min · 1.5" adult · Peaceful
Sterbai Corydoras
Corydoras sterbai
20 gal min · 2.5" adult · Peaceful
Sunset Honey Gourami
Trichogaster chuna
10 gal min · 2" adult · Peaceful
Venezuelan Corydoras
Corydoras venezuelanus
15 gal min · 2.5" adult · Peaceful
X-Ray Tetra
Pristella maxillaris
15 gal min · 1.75" adult · Peaceful
Black Kuhli Loach
Pangio oblonga
20 gal min · 4" adult · Peaceful
Black Molly
Poecilia sphenops
20 gal min · 3" adult · Peaceful
Black Moor Goldfish
Carassius auratus
20 gal min · 7" adult · Peaceful
Black Phantom Tetra
Megalamphodus megalopterus
15 gal min · 1.75" adult · Peaceful
Bloodfin Tetra
Aphyocharax anisitsi
15 gal min · 2" adult · Peaceful
Bumblebee Goby
Brachygobius xanthomelas
10 gal min · 1.5" adult · Semi-aggressive
Dwarf Chain Loach
Ambastaia sidthimunki
15 gal min · 2" adult · Peaceful
Dwarf Neon Rainbowfish
Melanotaenia praecox
15 gal min · 2.5" adult · Peaceful
Elephant Ear Betta
Betta splendens 'Dumbo'
5 gal min · 2.5" adult · Semi-aggressive
Emerald Eye Rasbora
Brevibora dorsiocellata
10 gal min · 1.5" adult · Peaceful
Emperor Tetra
Nematobrycon palmeri
15 gal min · 2" adult · Peaceful
Exclamation Point Rasbora
Boraras urophthalmoides
5 gal min · 0.8" adult · Peaceful
Florida Flagfish
Jordanella floridae
15 gal min · 2.5" adult · Semi-aggressive
Forktail Rainbowfish
Pseudomugil furcatus
10 gal min · 2" adult · Peaceful
GloFish Danio
Danio rerio
10 gal min · 2" adult · Peaceful
GloFish Tetra
Gymnocorymbus ternetzi
15 gal min · 2" adult · Peaceful
Glowlight Rasbora
Trigonostigma hengeli
10 gal min · 1.2" adult · Peaceful
Gold Honey Gourami
Trichogaster chuna
10 gal min · 2" adult · Peaceful
Hastatus Corydoras
Corydoras hastatus
10 gal min · 1" adult · Peaceful
Keyhole Cichlid
Cleithracara maronii
20 gal min · 3.5" adult · Peaceful
Kribensis
Pelvicachromis pulcher
20 gal min · 4" adult · Semi-aggressive
L066 King Tiger Pleco
Hypancistrus sp. L066
20 gal min · 3.5" adult · Peaceful
Least Killifish
Heterandria formosa
5 gal min · 1.5" adult · Peaceful
Macmasteri Dwarf Cichlid
Apistogramma macmasteri
20 gal min · 3" adult · Semi-aggressive
Mickey Mouse Platy
Xiphophorus maculatus
10 gal min · 2.5" adult · Peaceful
Mosquitofish
Gambusia affinis
10 gal min · 2.5" adult · Semi-aggressive
Neon Blue Dwarf Gourami
Trichogaster lalius
10 gal min · 3.5" adult · Peaceful
Neon Rasbora
Sundadanio axelrodi
10 gal min · 1.5" adult · Peaceful
Norman's Lampeye
Poropanchax normani
10 gal min · 1.5" adult · Peaceful
Not sure your combination fits?
Put your tank size and stock into the calculator — it checks bioload, schooling numbers and compatibility together.