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Freshwater Fish Profiles

Explore our growing database of freshwater fish species. Each profile includes detailed care requirements, compatibility data, and environmental needs to help you build the perfect aquarium.

Showing 1 - 24 of 602 Fish Profiles

Abei Puffer

Pao abei

Puffers
10.5 cm Highly Aggressive

A highly intelligent, interactive, and aggressive freshwater pufferfish native to the Mekong basin. They feature an earthy base color speckled with bright orange or pale spots. As true ambush predators and molluscivores, they require hard-shelled foods like snails and crustaceans to naturally file down their ever-growing teeth. Due to their extreme territoriality and formidable bite, they are widely considered a 'wet pet' and must be kept strictly alone.

Achara Catfish

Leiarius marmoratus

Catfish
80 cm Semi-Aggressive

A massive, striking Pimelodid catfish from South America. Known for its beautiful marbled pattern and remarkably long barbels. As a strictly predatory 'monster fish', it requires a gargantuan aquarium and massive filtration. While generally peaceful towards fish too large to swallow, it will eat anything that fits into its capacious mouth. Bare-bottom or soft sand is required to prevent fatal ingestion of gravel.

Adolfo Cory

Corydoras adolfoi

Catfish
6 cm Peaceful

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.

Adonis Pleco

Acanthicus adonis

Catfish
100 cm Aggressive

The Adonis Pleco is one of the largest and most formidable loricariids (plecos) in the world. While juveniles display stunning white polka dots on a pitch-black body, these spots fade into a solid dark grey/black as they mature into massive, heavily armored adults with long lyretails. Due to their enormous adult size (up to 1 meter/39 inches) and intense territorial aggression toward other bottom dwellers, they require giant, specialized aquariums or heated indoor ponds.

Aequidens Jenaro Herrera

Aequidens sp. 'Jenaro Herrera'

Cichlids - South American
18 cm Semi-Aggressive

An undescribed and beautifully colored South American cichlid hailing from the Peruvian Amazon (Rio Itaya/Ucayali drainages). Often confused in the trade with Aequidens diadema, this species features an attractive green-gold metallic sheen and reddish fins as it matures. They are relatively peaceful for mid-sized cichlids but will aggressively defend their territory during spawning and are capable predators of small fish.

Aequidens diadema (Diadem Cichlid)

Aequidens diadema

Cichlids - South American
15 cm Semi-Aggressive

A medium-sized, semi-aggressive South American cichlid native to the slow-moving rivers and blackwater streams of the Amazon basin. Known for their striking colors and strong personalities, they are omnivorous with a carnivorous tendency. Like many cichlids, they are notorious for digging and rearranging their habitat. They do well in large community tanks with appropriately sized tank mates but are fiercely intolerant of their own kind.

Aequidens sp. Atabapo

Aequidens sp. Atabapo

Cichlids - South American
15 cm Semi-Aggressive

A rare, undescribed species of Acara native to the blackwater Rio Atabapo in South America. They are characterized by small spots on the head and a typical robust, deep Aequidens body. Like other Acaras, they are moderately aggressive (especially when breeding) and thrive in very soft, warm, acidic water with sandy substrates and leaf litter.

Afra Cichlid

Cynotilapia afra

Cichlids - African
10 cm Aggressive

A highly active and aggressive Mbuna (rock-dwelling cichlid) endemic to Lake Malawi. Distinctive for their unicuspid 'dog-like' teeth, they natively feed on zooplankton in the water column but remain tied to rocky territories. They require a hard, alkaline water environment with abundant rockwork for hiding and establishing territories. Best kept in a densely stocked, carefully managed species harem or Mbuna community to disperse extreme aggression.

African Arowana

Heterotis niloticus

Oddballs
100 cm Mostly Peaceful

Unlike their South American or Asian counterparts, the African Arowana is a mid-to-bottom dwelling filter feeder that sifts sand for detritus, invertebrates, and small seeds. It is a massive, fast-growing species that requires a highly specialized diet of small sinking foods and an enormous aquarium. They are notoriously skittish and easily spooked.

African Butterfly Cichlid

Anomalochromis thomasi

Cichlids - African
7.5 cm Mostly Peaceful

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 Butterfly Fish

Pantodon buchholzi

Oddballs
12 cm Semi-Aggressive

A fascinating, prehistoric-looking surface dweller native to the slow-moving waters of West Africa. They are strictly top-dwelling ambush predators with a completely flat back and upturned mouth designed to hunt insects and small fish. A tight-fitting lid is absolutely mandatory as they are exceptional jumpers capable of gliding above the water.

African Clawed Frog

Xenopus laevis

Other
12 cm Aggressive

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.

African Dwarf Frog

Hymenochirus boettgeri

Other
4 cm Peaceful

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 Jewel Cichlid

Hemichromis bimaculatus

Cichlids - African
14 cm Aggressive

A strikingly beautiful but notoriously aggressive West African riverine cichlid. Unlike the alkaline-loving Rift Lake cichlids (e.g., Mbuna), Jewel Cichlids prefer neutral, softer water parameters. They are renowned for their brilliant red breeding dress and iridescent blue spots, but also for their extreme territoriality, especially when forming pairs and spawning. They are avid diggers and will uproot most plants.

African Knifefish

Xenomystus nigri

Oddballs
30 cm Semi-Aggressive

A fascinating nocturnal predator named for its blade-like shape. Lacking a dorsal fin, it moves by rippling its long anal fin, allowing it to easily swim backward and forward. While peaceful with larger tank mates, it is an opportunistic piscivore that will swallow any fish or invertebrate small enough to fit in its mouth. It requires dim lighting and plenty of caves (PVC or driftwood) to feel secure during the day.

African Lungfish

Protopterus annectens

Oddballs
100 cm Highly Aggressive

An ancient, fascinating oddball fish capable of surviving droughts by aestivating in mud cocoons. It is an obligate air-breather with a powerful bite. Highly predatory and completely intolerant of tank mates, it should be kept strictly solitary. Requires a heavy, secure lid as they are notorious and powerful escape artists.

African Pike

Hepsetus odoe

Characins
30 cm Aggressive

The African Pike is a formidable and fascinating predatory fish native to West and Central Africa. With its elongated, torpedo-shaped body and a mouth full of prominent sharp teeth, it is a surface-dwelling ambush predator that requires a massive aquarium. Best kept by advanced aquarists, they are heavily piscivorous and will consume any fish that fits in their mouths, though they are generally tolerant of similarly sized, robust tank mates.

African Pipefish

Enneacampus ansorgii

Oddballs
14 cm Peaceful

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

Catfish
6.5 cm Peaceful

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.

Agassiz's Dwarf Cichlid

Apistogramma agassizii

Cichlids - South American
7.5 cm Semi-Aggressive

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.

Ajamaru Rainbowfish

Melanotaenia ajamaruensis

Rainbowfish
11 cm Peaceful

A highly active, schooling rainbowfish endemic to the Ayamaru Lakes in West Papua, Indonesia. Currently listed as Critically Endangered in the wild. It is closely related to Boeseman's Rainbowfish but possesses a notably more slender body and more prominent reddish-brown horizontal striping. They thrive in hard, alkaline water with dense vegetation and require significant horizontal swimming space.

Allen's Rainbowfish

Chilatherina alleni

Rainbowfish
10 cm Peaceful

A rare and highly active rainbowfish native to West Papua, Indonesia (Wapoga River basin). Known as the 'Wapoga Rainbowfish', they undergo a dramatic color transformation as they mature, developing intense metallic blues, greens, and reds. As exceptionally fast, continuous swimmers, they require a 4-foot (120cm) aquarium minimum to thrive without stress.

Alligator Gar

Atractosteus spatula

Oddballs
200 cm Aggressive

A massive, primitive ambush predator native to North and Central America, known for its crocodilian snout and armor-like ganoid scales. They grow to enormous sizes and are strictly for public aquaria or highly advanced monster fish keepers with massive custom indoor ponds. They are air-breathers and incredibly hardy, but their size makes them entirely unsuitable for standard home aquariums.

Alligator Pleco

Pterygoplichthys scrophus

Catfish
28 cm Mostly Peaceful

The Alligator or Rhino Pleco is a large, heavily armored catfish easily identified by the prominent ridge along its back and its flared nasal passages. While an excellent algae eater and scavenger, it grows massive and produces an extreme amount of waste. It requires driftwood for grazing and digestion.