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.
Melanotaenia catherinae
A rare but beautiful schooling fish endemic to the streams and springs of Waigeo Island in West Papua, Indonesia. They are highly active, energetic mid-water swimmers. Like most rainbowfishes, they are peaceful and thrive in planted community tanks that still offer plenty of open swimming space. They display a distinctive, unusually wide mid-lateral stripe and reddish fins.
Clarias batrachus
An incredibly hardy, fast-growing predatory catfish infamous for its ability to 'walk' on dry land using its pectoral fins and breathe atmospheric air. It will quickly consume any fish that fits in its cavernous mouth and requires a massive aquarium with an absolutely secure, heavy lid to prevent escape.
Oreochromis hornorum
A robust, deep-bodied African cichlid native to the Wami River basin in Tanzania. Known for its extreme adaptability to poor water quality, high salinity, and varied diets, it is widely utilized in aquaculture. In the aquarium hobby, it requires a massive tank and heavy filtration. It is an opportunistic omnivore that will destroy most aquatic plants and eat smaller fish. Males are highly territorial, especially when defending spawning pits.
Lepomis gulosus
The Warmouth is a robust, highly predatory North American sunfish. Characterized by its cavernous mouth and dark, mottled brown coloration, it closely resembles a Rock Bass. It is highly aggressive and territorial, requiring a spacious tank. It will rapidly consume any tank mate small enough to fit in its large mouth and thrives in heavily structured aquariums mimicking slow-moving, weed-choked waters.
Polypterus weeksii
A prehistoric, heavily-armored predatory fish from the Congo River basin. Known for its distinctively large head, thick body, and prominent dorsal finlets. They possess functional lungs and must breathe atmospheric air. While peaceful toward fish too large to swallow, they are highly predatory and will consume anything that fits in their spacious mouths. They are notorious escape artists.
Silurus glanis
The Wels Catfish is a massive, highly predatory freshwater fish native to Eastern Europe and parts of Asia. As one of the largest freshwater fish in the world, it is wholly unsuited for standard home aquariums and requires a heavy-duty heated indoor pond or massive custom setup. They are highly opportunistic predators that will swallow any tank mate that fits into their enormous mouths.
Polypterus retropinnis
An ancient, primitive fish with a snakelike body and a lung-like swim bladder that allows it to breathe atmospheric air. The West African Bichir is a nocturnal bottom-dweller that relies on an excellent sense of smell to hunt. While surprisingly peaceful towards large tankmates, it is highly predatory and will swallow any fish that fits in its mouth. It requires a tight-fitting lid as it is a notorious escape artist.
Melanotaenia australis
An energetic, colorful schooling fish native to Northwestern Australia. They display prominent lateral zigzag lines and bright red or orange fins. Known for their active nature, they require plenty of horizontal swimming space and should be kept in schools to reduce stress and encourage males to display their best colors. They are boisterous feeders that may outcompete shy fish.
Rineloricaria sp.
A highly cryptic, peaceful, and extremely slender catfish that mimics a twig or dead leaf. They are excellent scavengers and biofilm grazers that require smooth sand and driftwood to thrive. They are completely non-aggressive, lack the heavy armor of larger plecos, and do well in peaceful community setups.
Macrobrachium sp.
Often accidentally sold as the peaceful Ghost Shrimp, the Whisker Shrimp is a larger, highly aggressive freshwater prawn. They can be easily identified by their unusually long antennae ('whiskers') and prominent, elongated front claws. They are opportunistic hunters that will actively prey on dwarf shrimp, fry, and even small sleeping community fish.
Rhinogobius duospilus
A small, highly entertaining benthic fish native to fast-flowing, highly oxygenated hillstreams in Southern China and Hong Kong. They lack a functional swim bladder, instead using modified pelvic fins to 'hop' and cling to smooth river rocks. They require cooler water temperatures and strong flow. Males are famous for their flared-fin displays and territorial squabbles.
Vieja argentea
A striking, large Central American cichlid known for its brilliant silvery-white body speckled with black markings. Currently reclassified by many as Maskaheros argenteus, they are powerful, highly territorial fish. As herbivores/omnivores, they are notorious for shredding live plants and rearranging the tank substrate.
Tanichthys albonubes
A hardy, peaceful, and active schooling fish famous for its ability to thrive in unheated, sub-tropical aquariums. Native to the mountain streams of China, they feature a bronze body with a striking neon-like lateral stripe and red-tipped fins. They are strictly schooling fish and must be kept in groups to feel secure and display their best colors.
Andinoacara stalsbergi
Often sold interchangeably under the name 'Green Terror', Andinoacara stalsbergi (the White Saum) is a highly aggressive and territorial South American cichlid. It differs from the true Green Terror (A. rivulatus / Gold Saum) by having striking white edging on its fins rather than orange. They require large tanks, excellent filtration, and are best kept singly or with other robust, similar-sized fish that can hold their own.
Cynotilapia sp. 'hara'
A popular and striking Mbuna from Lake Malawi's Gallireya Reef. Males boast a bright white upper body with distinct dark vertical barring, while females are more subdued. Like most Mbuna, they are aggressive, rock-dwelling grazers requiring alkaline water, sand for digging, and strict harem breeding groups (1 male to multiple females) to manage aggression.
Betta albimarginata
A small, fascinating wild Betta species native to the shallow forest streams of Borneo. Unlike the common Betta splendens, the Whiteseam Fighter is a paternal mouthbrooder and is significantly more peaceful. They are a strict blackwater species requiring very soft, acidic water heavily tinted with tannins. They are notorious jumpers, so a tight-fitting lid is absolutely mandatory.
Parachromis dovii
The Wolf Cichlid is an apex predator and one of the largest, most notoriously aggressive cichlids in the aquarium hobby. Possessing immense jaw strength and explosive power, they require massive, heavy-duty aquariums. They are almost strictly kept as solitary 'wet pets' because they will systematically hunt and kill nearly any tank mate.
Hoplias malabaricus
A highly aggressive, apex ambush predator native to South America. Known for its dog-like teeth and immense jaw strength, the Wolf Fish is best kept in a solitary species tank. They are notorious jumpers and require a heavy, tight-fitting lid. Not for beginners.
Dermogenys pusilla
A unique, surface-dwelling livebearer known for its elongated, pike-like lower jaw. Males are famous for 'wrestling' by locking jaws to establish dominance. They are strictly top-dwellers and excellent jumpers, requiring a tight-fitting lid to prevent escapes and snout injuries. They prefer hard, alkaline water and thrive in both freshwater and slightly brackish conditions.
Pristella maxillaris
A remarkably hardy and peaceful schooling fish, named for its translucent body that reveals its internal organs. Uniquely among tetras, it naturally inhabits both fresh and slightly brackish coastal waters in South America, making it incredibly adaptable to various aquarium conditions. An excellent choice for beginners.
Xenotilapia ochrogenys
A fascinating sand-sifting cichlid endemic to Lake Tanganyika. They require a large-footprint tank with fine sand, which they constantly sift through their gills to extract benthic invertebrates. They are easily startled and are notorious jumpers, so a tight-fitting lid is essential. Because of their harem-breeding dynamics, they must be kept in groups.
Xenotilapia papilio
A stunning, highly specialized benthic cichlid endemic to Lake Tanganyika. Unlike many open-sand dwelling Xenotilapia, the Papilio prefers deeper rocky habitats interspersed with sand. They feed by sifting sand through their gills to extract micro-invertebrates. While peaceful toward other species, they are extremely intolerant of conspecifics once mature; they form monogamous, biparental mouthbrooding pairs that vigorously defend their rock territory. A soft, fine sandy substrate is strictly required to prevent fatal gill damage.
Aequidens metae
A medium-sized, relatively peaceful South American cichlid native to the Meta River basin. They possess a yellowish-brown body with distinct dark vertical barring and iridescent spangling. While less aggressive than many other cichlids, they are territorial, especially during spawning, and will readily consume fish small enough to fit in their mouths.
Ameiurus natalis
A robust, highly adaptable North American catfish. Primarily nocturnal and opportunistic, it will consume anything that fits into its wide mouth. Best kept in coldwater to temperate predator setups with heavy filtration, as they produce massive bioloads, uproot plants, and eat smaller tank mates.
