Explore all oddballs in our database. Browse detailed care guides, compatibility information, and species data to find the perfect fish for your aquarium.
Heterotis niloticus
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.
Pantodon buchholzi
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.
Xenomystus nigri
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.
Protopterus annectens
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.
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.
Atractosteus spatula
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.
Plesiotrygon iwamae
The Antennae Stingray is a delicate, rare freshwater ray native to the Amazon basin. It is distinctive for its extremely long, whip-like tail that can be more than twice its disc width. They require a massive aquarium with an enormous footprint, pristine water quality, and a soft, fine sand substrate to bury themselves. As large piscivores, they will consume any tank mate small enough to fit in their mouths.
Arapaima gigas
One of the largest true freshwater fish in the world, native to the Amazon basin. Arapaima are obligate air-breathers and extreme predators. Due to their massive adult size and explosive growth rate, they are almost entirely unsuited for home aquaria and require highly specialized, heated, pond-sized enclosures.
Scleropages formosus
A highly prized, CITES-protected 'monster fish' known as the Dragon Fish. They are powerful, surface-dwelling predators that require massive aquariums and pristine water quality. Notorious jumpers, they require heavy, secure lids. Because of intense territoriality, they must be kept strictly solitary or in large 'comm' (community) groups of 5+ to disperse aggression.
Scleropages jardinii
A massive, highly aggressive predatory fish native to Australia and New Guinea. Known for its distinct metallic, pearl-like scales and upward-facing mouth designed for surface feeding. It is notoriously territorial and intolerant of tank mates, making it a popular 'wet pet' for solitary setups. It is an absolute tank buster requiring a massive aquarium with a heavy, tightly secured lid to prevent fatal jumping.
Toxotes jaculatrix
Famous for their ability to shoot down insects with a precise jet of water. As surface-dwelling predators native to mangrove estuaries, they require hard, brackish water to thrive long-term. They have a high prey drive and will eat any fish small enough to fit in their mouths. A tight-fitting lid is absolutely mandatory as they are exceptional jumpers.
Apteronotus albifrons
A fascinating nocturnal predator native to the Amazon basin. It lacks a dorsal fin and moves via a continuous undulating ventral fin, allowing it to swim backwards as easily as forwards. It generates a weak electrical field to navigate and hunt in the dark. Scaleless and highly sensitive to medications, it requires smooth hiding places (like PVC pipes or smooth driftwood). Will consume any fish small enough to fit in its surprisingly large mouth.
Polypterus palmas buettikoferi
The Buettikoferi Bichir (often sold as the Gold Dust Bichir) is a fascinating ancient fish native to West Africa. Like all bichirs, it possesses a modified swim bladder acting as a primitive lung, requiring a small air gap at the surface to breathe atmospheric air. They are peaceful towards similarly-sized fish but are highly predatory nocturnal ambushers that will consume anything that fits in their mouths.
Channa marulius
A massive, apex-predator fish native to South Asia. The Bullseye Snakehead is one of the largest snakehead species, capable of reaching lengths up to 4-6 feet (120-180cm). They possess a suprabranchial organ allowing them to breathe atmospheric air. Due to their extreme size, intense aggression, and powerful jumping ability, they are strictly for advanced monster-fish keepers with indoor ponds or massive custom enclosures.
Chitala ornata
A massive, nocturnal predator native to Southeast Asia, widely known for the distinct row of ocellated spots above its anal fin. While sold as small silvery cute juveniles, they grow incredibly fast into nearly 1-meter giants that require immense aquariums. They are obligate carnivores and will eat any fish small enough to fit in their large mouths. They are shy during the day and require large hiding tubes or caves.
Polypterus endlicheri congicus
The Congo Bichir is a prehistoric-looking, bottom-dwelling monster fish and one of the largest species in the Polypteridae family. They are obligate air-breathers and ambush predators that will eagerly consume any tankmate small enough to fit in their surprisingly large mouths. Due to their massive adult size, they require extremely large custom aquariums, heavy filtration, and a tight-fitting lid to prevent escapes.
Atractosteus tristoechus
The Cuban Gar (Manjuarí) is a massive, ancient ambush predator native to the fresh and brackish waters of Cuba. It features a crocodilian snout, heavy armor-like scales, and a torpedo-shaped body. Due to its extreme adult size, it is strictly recommended only for expert aquarists with indoor ponds or enormous custom tanks. It will swallow any tank mate small enough to fit in its jaws, but generally ignores fish that are too large to eat.
Polypterus delhezi
An ancient, air-breathing predatory fish from the Congo River basin. Known for its distinct black vertical bands and dinosaur-like dorsal finlets. They are bottom-dwelling ambush predators with poor eyesight but an excellent sense of smell. While generally peaceful with similarly sized or larger fish, they are opportunistic piscivores and will eat anything that fits into their surprisingly large mouths.
Channa marulioides
The Emperor Snakehead is a massive, highly predatory oddball native to the rivers and lakes of Southeast Asia. Known for striking adult coloration featuring bright orange rosettes (flowers) along their flanks, they are top-tier monster fish. They are obligate air-breathers (requiring access to the surface) and incredibly strong jumpers. Due to their massive adult size and highly aggressive nature, they require specialized, enormous aquariums and should only be kept by experienced monster fish keepers.
Monodactylus argenteus
The Silver Mono, or Finger Fish, is a stunning, fast-moving schooling fish known for its shiny, diamond-shaped body. They are euryhaline; juveniles inhabit freshwater or brackish estuaries, but adults require high-end brackish or full marine setups to thrive. They are active, voracious eaters that must be kept in groups to curb fin-nipping and internal aggression.
Mastacembelus erythrotaenia
The Fire Eel is a stunning, large species of spiny eel native to Southeast Asia, known for its brilliant red lateral stripes and highly interactive, 'dog-like' personality with owners. As a true 'monster fish', it requires massive aquariums. A soft sand substrate is absolutely mandatory, as they will burrow and suffer lethal bacterial infections from scratching themselves on gravel. They are notorious escape artists and will eat any fish small enough to fit in their mouths.
Lepisosteus platyrhincus
A prehistoric, heavily armored ambush predator native to the southeastern United States. They possess an elongated, torpedo-like body and a beak filled with sharp teeth. As an apex predator, they will consume any tank mate that fits in their mouths, but are generally peaceful toward fish too large to eat. They require massive aquariums and a secure, weighted lid due to their powerful jumping capability.
Potamotrygon schroederi
A stunning, large-growing freshwater stingray native to the Rio Negro and Orinoco basins. They feature intricate rosette or flower-like patterns. As apex predators, they require massive aquariums, exceptional biological filtration due to extreme bioloads, and a fine sand substrate to prevent injury to their soft bellies. They possess a venomous tail barb and must be handled with extreme caution.
Trinectes maculatus
Despite the trade name 'Freshwater Flounder', Trinectes maculatus is actually a euryhaline flatfish native to coastal estuaries in North America. While juveniles migrate into fresh water, adults require at least low-end brackish water (SG 1.005+) for long-term health and a normal lifespan. They are highly specialized, nocturnal ambush predators that spend most of their time buried in fine sand. Keeping them on sharp gravel will severely damage their undersides and lead to infection.
