20 Gallon High
A taller footprint that favors mid-to-top swimming fish like Hatchetfish, Guppies, and Platies.
Similar Tanks & Sizes
A taller footprint that favors mid-to-top swimming fish like Hatchetfish, Guppies, and Platies. With a capacity of 76 litres (20 gallons) and dimensions of 61 x 30 x 41, this high tank is compatible with 167 species in our database — giving you plenty of options for a thriving community setup.
Tank equipment picks
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Stocking Tips
- 💡Larger tanks are more forgiving, but always add fish gradually — introduce 2–3 species at a time to let the biological filter adapt.
- 💡Mix species from different swim zones (top, middle, bottom) to make use of the full water column.
Stocking Recipes
Pre-built species combinations that work well together in this tank.
Peaceful Community
- Apistogramma Mamoré×1Centerpiece
- Chili Rasbora×6Schooling
- African Pipefish×1Bottom Dweller
Bold & Beautiful
- Red Swamp Crayfish×1Centerpiece
- Dwarf Molly×6Schooling
- African Butterfly Cichlid×1Bottom Dweller
Nano-Friendly Mix
- Chili Rasbora×6Schooling
- Bladder Snail (Pest Snail)×1Bottom Dweller
Gentle Giants
- African Clawed Frog×1Centerpiece
- Australian Smelt×6Schooling
- Banjo Catfish×1Bottom Dweller
Low Maintenance Setup
- Chili Rasbora×6Schooling
- Bee Shrimp (Crystal Red / Black)×10Bottom Dweller
Schooling Showcase
- Chili Rasbora×6Schooling
- Agassiz Cory×6Bottom Dweller
Water and maintenance products
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Commonly Mis-Stocked
These fish are frequently added to this tank but may outgrow it or cause problems. Proceed with caution.
African Clawed Frog fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Amazon Puffer requires at least 75cm of swimming length, which is 23% longer than this tank's 61cm.
American Grass Shrimp fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Arrowhead Puffer requires at least 75cm of swimming length, which is 23% longer than this tank's 61cm.
Australian Smelt fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Bladder Snail (Pest Snail) fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Blue Pearl Shrimp fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Blue Tetra needs at least 90L, which is 18% more than this tank's 76L capacity.
Cherry Shrimp fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Convict Cichlid requires at least 75cm of swimming length, which is 23% longer than this tank's 61cm.
Dusky Millions Fish fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Dwarf Molly fits this tank now but grows rapidly — monitor closely and be prepared to upgrade.
Show 19 more warnings
Centerpiece Fish
Bold, eye-catching species that serve as the focal point of your tank. Typically kept singly or in pairs.
African Clawed Frog
Xenopus laevis
A fully aquatic, highly active amphibian. DO NOT confuse with the peaceful, nano-sized African Dwarf Frog. The African Clawed Frog grows much larger and will voraciously eat any fish or invertebrate that fits in its mouth. They lack teeth and tongues, using their clawed, webbed hands to shovel food into their mouths. They require a tight-fitting lid (they are notorious escape artists) and prefer cooler water, low flow, and smooth substrate to protect their sensitive skin.
Agassiz's Dwarf Cichlid
Apistogramma agassizii
A stunning South American dwarf cichlid known for its distinct spade-shaped tail and brilliant color morphs. They are bottom-dwelling micro-predators that sift sand for food. While generally peaceful in community tanks, they are highly territorial when breeding. They thrive in soft, acidic blackwater conditions.
Apistogramma Black-Chin
Apistogramma allpahuayo
A stunning dwarf cichlid from the blackwaters of Peru, formerly known as Apistogramma sp. 'Black-Chin' until it was scientifically described as A. allpahuayo in 2012. It is famous for the male's distinct pitch-black chin and its unique ability among Apistogrammas to undergo functional sex change (a female can morph into a functional male if the dominant male dies). They are harem breeders that require pristine, highly acidic water with leaf litter and a sandy substrate.
Apistogramma Mamoré
Apistogramma erythrura
Formally described as Apistogramma erythrura in 2008, this species was heavily traded for years under the name Apistogramma sp. 'Mamoré'. Native to the Mamoré River basin in Bolivia, they are highly sought after for the adult male's vibrant red caudal fin and elongated finnage. As benthophagous cichlids, they require a soft, sandy substrate to sift through, along with ample visual barriers like leaf litter and driftwood to feel secure.
Apistogramma Marmor (Marbled Apisto)
Apistogramma erythrura
The Marbled Apisto is a beautiful, diminutive South American dwarf cichlid. Like most Apistogramma species, they are bottom-dwelling micropredators that naturally sift through fine sand and leaf litter for food. They require soft, acidic water, gentle flow, and plenty of visual barriers like driftwood and caves to feel secure. As harem breeders, a typical setup includes one male and several females.
Apistogramma Mouthbrooder (Maulbrüter)
Apistogramma barlowi
Formally described as Apistogramma barlowi, this species is highly unique among Apistogramma. Unlike its cousins who are strict cave-spawners, the Maulbrüter is a facultative larvophilous mouthbrooder. They spawn in caves, but once the eggs hatch, the female (and occasionally the male) will gather the larvae in their mouths to protect them. They require soft, acidic blackwater conditions and sandy substrate.
Show 43 more centerpiece fish
Schooling Fish
Active swimmers best kept in groups. They bring movement and colour to the mid and upper levels of your tank.
Australian Smelt
Retropinna semoni
A slender, silvery schooling fish native to Australia. They are pelagic and found in huge numbers in the wild across freshwater rivers, billabongs, and brackish estuaries. Known for their distinct cucumber-like odor when handled. In the aquarium, they are highly sensitive to handling and require mature, stable water with plenty of open swimming space. Best kept in single-species setups or with very peaceful, temperate tank mates.
Beckford's Pencilfish
Nannostomus beckfordi
A peaceful, slender schooling fish native to the sluggish rivers and swamps of South America. They are famous for the males' harmless but spectacular lateral sparring displays. They require heavily planted aquariums with gentle flow and make excellent tank mates for other peaceful, soft-water species. A tight-fitting lid is essential as they are known to be proficient jumpers.
Black Neon Tetra
Hyphessobrycon herbertaxelrodi
A peaceful, active schooling fish native to the Paraguay basin. Known for its striking contrast of a dark black lateral stripe underneath a glowing iridescent white/green-gold stripe. Excellent for community aquariums, particularly in planted setups or blackwater biotope tanks with subdued lighting.
Black Phantom Tetra
Hyphessobrycon megalopterus
A peaceful, deep-bodied schooling tetra native to the Guaporé and Paraguay river basins. They are named for the distinct 'phantom' black patch behind their gills. They thrive in heavily planted tanks with subdued lighting (often achieved via floating plants or blackwater conditions). Males engage in spectacular but harmless 'mock battles' where they flare their fins at each other.
Blackline Rasbora
Rasbora borapetensis
The Blackline Rasbora, often sold as the Red-tailed Rasbora, is a hardy and highly active schooling fish native to Southeast Asia. Recognizable by a bold black lateral line topped with gold and a bright red caudal fin, they are peaceful but energetic. They require plenty of horizontal swimming space in the middle to upper levels of the aquarium and must be kept in schools to feel secure.
Bloodfin Tetra
Aphyocharax anisitsi
An extremely hardy and energetic schooling fish characterized by its silver body and striking bright red fins. As exceptionally active swimmers, they require plenty of horizontal swimming space. They are very adaptable to temperature and water parameters, making them a fantastic choice for beginners. Must be kept in groups to curb minor fin-nipping tendencies.
Show 35 more schooling fish
Bottom Dwellers
Species that inhabit the lower reaches of the aquarium, helping keep the substrate clean and adding activity to the tank floor.
Adolfo Cory
Corydoras adolfoi
Adolfo's Corydoras is a highly sought-after, peaceful schooling catfish native to the blackwater habitats of the Rio Negro basin. They are easily identified by their bright orange nape and distinct black eye stripe. Like all corydoras, they require soft sand substrate to protect their delicate sensory barbels as they constantly sift the bottom for food.
African Butterfly Cichlid
Anomalochromis thomasi
A peaceful, colorful dwarf cichlid from West Africa. Unlike many cichlids, it is plant-safe and generally suitable for community tanks. It is famous in the hobby as an efficient biological control for pest snails.
African Dwarf Frog
Hymenochirus boettgeri
A fully aquatic amphibian that is peaceful and highly entertaining. They possess lungs and must regularly dart to the surface to breathe air, so tank height should ideally be under 40cm (15 inches). Due to their poor eyesight, they hunt by smell and tactile vibration, making them slow feeders that can easily starve if housed with fast, aggressive fish. They are social creatures that thrive in small groups.
African Pipefish
Enneacampus ansorgii
The African Pipefish is a fascinating, needle-thin relative of the seahorse native to West African streams. They are considered an expert-level oddball because they are very weak swimmers and almost exclusively require tiny live foods (like baby brine shrimp, daphnia, or micro-fauna). They are highly peaceful but will easily starve if housed with fast-moving community fish that outcompete them for food.
Agassiz Cory
Corydoras agassizii
A peaceful, bottom-dwelling armored catfish native to the Amazon River basin. They are easily identified by their silvery body with dark spots and a distinct black mask over their eyes. Like all Corydoras, they are highly social and must be kept in groups. A soft sand substrate is absolutely essential to protect their delicate sensory barbels as they forage.
Amano Shrimp
Caridina multidentata
A highly popular, industrious freshwater shrimp renowned for its unmatched algae-eating abilities. Popularized by aquascaper Takashi Amano, they are significantly larger and hardier than most dwarf shrimp (like Cherry Shrimp). They are notorious food-thieves during feeding time and excellent escape artists, requiring a tight-fitting lid. Their larvae require saltwater to develop, so they will not overpopulate in a freshwater aquarium.
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Other Compatible Species
Additional species that are compatible with this tank size but don't fall neatly into the categories above.
Amazon Leaf Fish
Monocirrhus polyacanthus
A master of camouflage that perfectly mimics a dead leaf drifting in the water. This species is an extreme ambush predator with a protruding jaw that can swallow prey up to 75% of its own size. It is a 'specialist' species because nearly all specimens require live food (small fish/shrimp) and refuse dry or frozen foods. Requires acidic, blackwater conditions and zero flow.
Balloon Molly
Poecilia latipinna hybrid
A selectively bred morphological variant characterized by a shortened spine and a rounded, balloon-like belly. Due to their altered anatomy, they are poorer swimmers than standard mollies and are prone to digestive and swim bladder issues. Like all mollies, they thrive in hard, alkaline water, appreciate algae in their diet, and are highly tolerant of brackish conditions.
Betta Imbellis
Betta imbellis
Known as the 'Peaceful Betta', Betta imbellis is a wild species closely related to Betta splendens. Unlike their highly aggressive domestic cousins, they can often be kept in pairs or carefully managed groups. They are native to blackwater swamps and require calm, tannin-stained water with plenty of cover. They are exceptionally prone to jumping.
Endler's Livebearer
Poecilia wingei
A tiny, vibrant, and highly active livebearer closely related to the Guppy. Males display intense, neon colors and patterns, while females are larger and plainly colored. They are prolific breeders and require hard, alkaline water to thrive.
Guppy
Poecilia reticulata
One of the most iconic and widely kept aquarium fish. Renowned for their incredible colors, hardiness, and prolific breeding. As livebearers, they give birth to fully formed, free-swimming fry. Males constantly pursue females for mating; therefore, a ratio of at least 2 females per male is strongly recommended to disperse stress.
Honey Gourami
Trichogaster chuna
The smallest and most peaceful member of the Trichogaster genus. Ideally suited for planted nano aquariums. Unlike the aggressive Dwarf Gourami (*T. lalius*), Honey Gouramis are timid and gentle. True Honey Gouramis rarely exceed 5cm. Note: Many bright red fish sold as 'Red Honey' or 'Red Robin' are actually Thick-lipped Gouramis (*T. labiosa*), which grow larger.
Show 2 more other compatible species
Frequently Asked Questions — 20 Gallon High
How many fish can I put in a 20 Gallon High?
The 20 Gallon High (76 L / 20 gal) is compatible with 167 species in our database. The actual number of individual fish depends on the species mix — use the stocking recipes above as a starting point and aim to keep the total bioload below 85% of capacity.
What is the best centrepiece fish for a 20 Gallon High?
Popular centrepiece options for this tank include African Clawed Frog, Agassiz's Dwarf Cichlid, Apistogramma Black-Chin. A centrepiece fish should be the focal point of your aquarium — choose one with colours and behaviour that complement your other species.
What schooling fish work in a 20 Gallon High?
Great schooling options include Australian Smelt, Beckford's Pencilfish, Black Neon Tetra. Schooling fish should be kept in groups of at least 6 to encourage natural behaviour and reduce stress.
What bottom dwellers suit a 20 Gallon High?
Suitable bottom dwellers include Adolfo Cory, African Butterfly Cichlid, African Dwarf Frog. These species occupy the lower zone of your tank, helping to keep the substrate tidy and adding activity to an often-overlooked area.
What temperature should a 20 Gallon High be?
The ideal temperature depends on the species you keep. Most tropical freshwater fish thrive between 24–27°C (75–80°F). Check each species' requirements and aim for the overlapping range that suits all your inhabitants.