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.
Pseudomugil signifer
An energetic and highly adaptable blue-eye species native to Eastern Australia. They inhabit a massive range of environments from rainforest streams to full-marine mangrove estuaries. Known for their striking blue eyes and the male's butterfly-like fin displays. They must be kept in schools, where males will constantly spar and flash their colors.
Acipenser transmontanus
The Pacific (or White) Sturgeon is the largest freshwater fish in North America. As a true 'monster fish', it requires an absolutely massive indoor facility or an outdoor pond. They are coldwater, anadromous fish that require high oxygen levels, fast flow, and a soft sandy substrate to protect their sensitive sensory barbels. They are strict bottom feeders and will inadvertently swallow small tank mates.
Polypterus palmas palmas
An ancient, primitive bottom-dweller from West Africa known for its dinosaur-like appearance and ability to breathe atmospheric air using modified lungs. While it is one of the smaller 'upper jaw' Bichir species, it is a highly capable ambush predator. It is generally peaceful towards fish too large to swallow, but completely unsafe for small community fish. A tight-fitting lid is absolutely mandatory to prevent escaping.
Corydoras panda
A highly popular, peaceful schooling catfish easily identified by its black eye patches and spotted dorsal/tail fins, resembling a giant panda. Native to the cooler waters of the Ucayali river system in Peru, they require slightly lower temperatures than many standard tropical community fish. They are strict bottom-dwellers that sift through the substrate for food.
Apistogramma nijsseni
A striking South American dwarf cichlid native to blackwater habitats in Peru. Famous for the female's bright yellow coloration and distinct 'panda' black blotches. Males are larger with a blue-yellow sheen and a red-edged rounded tail. They require soft, acidic water, leaf litter, and fine sand to sift through.
Garra flavatra
A highly active, beautifully patterned benthic (bottom-dwelling) fish native to the fast-flowing, highly oxygenated streams of Myanmar. They are excellent biofilm and algae grazers. While peaceful towards other species, they establish a strict, sometimes physical pecking order among themselves. They are notorious climbers and jumpers, requiring a tight-fitting lid.
Aphyocharax paraguayensis
A small, highly active, and strikingly marked characin native to the Paraguay River basin. Known as the Panda or Dawn Tetra, it features a metallic silver body with distinctive black and white markings on its tail and anal fins. While beautiful and hardy, they are notorious fin-nippers. They must be kept in larger schools to disperse aggression and should never be housed with slow-moving or long-finned fish (like Bettas or Angelfish).
Pangasius nasutus
A massive riverine shark-catfish native to Southeast Asia. It is an extremely active 'tank buster' that reaches up to 90cm (3 feet) in length. They are easily startled, prone to panic attacks, and can severely injure themselves by smashing into the aquarium glass. Due to their immense adult size, they are strictly suited for massive custom aquariums or heated indoor ponds.
Parathelphusa pantherina
A striking, fully aquatic freshwater crab endemic to Lake Matano in Sulawesi, Indonesia. Recognizable by its pale yellow-orange body covered in dark panther-like spots. They are opportunistic scavengers and predators that will hunt snails, shrimp, and bottom-dwelling or sleeping fish. They are notorious escape artists and require a very tight-fitting lid. Unlike many crabs, they do not require a land area, though they need plenty of underwater rock caves.
Macropodus opercularis
One of the first ornamental fish in the hobby (pre-dating the Goldfish in Europe). Paradise Fish are stunning, hardy, subtropical Anabantoids. However, they are notoriously aggressive, often exceeding the aggression of Bettas. They are cold-tolerant and thrive in unheated indoor aquariums, but they will readily attack smaller tank mates, eat fry, and fight conspecifics to the death.
Corydoras parallelus
A highly sought-after and relatively rare Corydoras species native to the upper Rio Negro basin. They are instantly recognizable by the striking black and white parallel stripes running along their flanks. Like all Corydoras, they are peaceful, strictly bottom-dwelling shoaling fish that must be kept in groups. They require a soft sand substrate to protect their delicate barbels as they forage for food.
Melanotaenia parkinsoni
A large, incredibly active schooling fish native to Papua New Guinea. They are highly prized for the dramatic, ragged splotches of bright orange or yellow that develop on the males. Like most large rainbowfish, they require highly oxygenated, slightly alkaline water and a long aquarium to accommodate their constant swimming.
Loricaria parnahybae
A distinctive, slender armored catfish native to the Parnaíba River basin in Brazil. Known for its extremely elongated tail and flattened body, it blends perfectly with sandy substrates. It is a peaceful, fascinating bottom-dweller. Like other members of the genus Loricaria, they are remarkable 'lip brooders', where males carry clusters of eggs attached to their enlarged lower lips until they hatch.
Hoplarchus psittacus
The 'True' Parrot Cichlid is a large, stunning South American species known for its brilliant emerald green coloration and distinctive dark facial markings. It should NOT be confused with the man-made 'Blood Parrot' hybrid. Originating from blackwater rivers, it is highly sensitive to water quality and requires pristine, warm, soft, and acidic water. Due to its massive adult size, it requires a massive aquarium and will consume any fish small enough to fit in its mouth.
Cribroheros alfari
A strikingly beautiful Central American cichlid known for its pastel yellow, pink, and blue iridescent coloration. It is a substrate-sifting species that loves to dig in sand. Like many Central American cichlids, it can be highly territorial and aggressive, especially during breeding. Requires robust filtration and spacious quarters.
Hydrolycus scomberoides
The Payara, commonly known as the Vampire Tetra, is a formidable predatory fish famous for its prominent, sabre-like fangs used to spear prey. Native to fast-flowing rivers and rapids in the Amazon basin, they require enormous aquariums with pristine, highly oxygenated water and massive filtration. As strict piscivores, they will consume any fish small enough to fit in their mouths. Due to their enormous size and specialized needs, they are only suitable for expert aquarists with massive custom aquariums.
Cichla monoculus
A massive, powerful apex predator native to the Amazon basin. Known for their striking colors and explosive feeding strikes, Peacock Bass require enormous aquariums and heavy filtration. As dedicated piscivores, they will consume any fish small enough to fit in their cavernous mouths.
Cichla ocellaris
A massive, incredibly fast-swimming predatory cichlid native to South America. Known for their striking colors and voracious appetite, they are strictly for advanced 'monster fish' keepers. They possess highly expandable mouths and will eat absolutely any fish that fits inside. Despite their predatory nature, they are generally not aggressive towards tank mates they cannot swallow.
Cichla orinocensis
A massive, highly predatory South American cichlid native to the Orinoco and Rio Negro basins. Famous for its vibrant coloration and three distinct circular rosettes (ocelli) on its sides. They grow extremely fast and require enormous aquariums with heavy filtration. They are apex predators that will consume any fish that fits into their large mouths.
Cichla temensis
The undisputed king of the Peacock Bass family and one of the largest cichlids in the world. Native to the Amazon basin, they are apex open-water predators. In the aquarium hobby, they are true 'monster fish' requiring massive, custom-built tanks or indoor ponds and exceptional filtration due to their enormous bioload and strictly piscivorous diet.
Aulonocara sp.
Endemic to Lake Malawi, Peacock Cichlids are highly sought after for the breathtaking colors of the males. They are benthivorous, using sensory pores on their jaws to hunt small invertebrates in the sand. While territorial, they are generally peaceful compared to their aggressive Mbuna cousins. They require hard, alkaline water and a sandy substrate to prevent gill damage while sifting.
Macrognathus siamensis
A peaceful, nocturnal spiny eel native to Southeast Asia, easily identified by the false eyespots (ocelli) along its dorsal fin. They are notorious escape artists and avid burrowers. A soft sand substrate is absolutely mandatory to prevent severe bacterial skin infections from scratching, along with a tight-fitting lid. They are picky eaters that generally require live or frozen meaty foods like bloodworms.
Tateurndina ocellicauda
A stunning, peaceful freshwater sleeper goby from Papua New Guinea. Known for their vibrant blue, red, and yellow colors, they are excellent nano-tank inhabitants. They are not true gobies (they lack fused pelvic fins) and are exclusively freshwater. They prefer slow-moving water, dense vegetation, and small caves (like PVC pipes or smooth stones) for spawning.
Danio albolineatus
A highly active, schooling cyprinid native to the clear, flowing streams of Southeast Asia. Known for their iridescent, pearlescent bodies that shimmer under aquarium lighting with hints of blue, pink, and orange. They are very hardy but require significant horizontal swimming space and a tight-fitting lid due to their notorious jumping ability.
