Search Species
Search for fish species by common or scientific name, or use filters to browse by water type, size, temperament, and difficulty.
Found 563 species
Roule's abyssal cusk
Barathronus roulei
Barathronus roulei is a deep-sea bythitid/brotula-type fish from the Northeast Atlantic, recorded from deep water (e.g., ~1349 m). It is extremely rarely encountered and not an aquarium species due to collection and decompression/pressure constraints.
Roule's smooth-head
Rouleina livida
Rouleina livida is a deep-sea slickhead (family Alepocephalidae) that lives way down in the bathypelagic zone, not something you will ever see in the aquarium trade. It tops out around 34 cm standard length and has those classic deep-sea vibes like huge eyes plus little light organs (photophores) around the head and jaw.
Roundel batfish
Zalieutes elater
Zalieutes elater is a weird little "walking" batfish that lives on sand and mud bottoms and basically scoots around like a tiny sea creature robot. The coolest giveaway is the pair of orange-and-black eye-spots (ocelli) on its back, plus it has a short anglerfish-style lure it uses to ambush small crustaceans and fish.
Ruaha kneria
Kneria ruaha
Kneria ruaha is a small Tanzanian freshwater shellear (Kneriidae) from the Ruaha River basin. It inhabits cool, quiet stream sections and feeds on detritus in the wild; aquarium husbandry guidance is sparsely documented, so keep in a mature, oxygen-rich tank and offer a varied small sinking diet alongside natural grazing.
Rubenstein's nannocharax
Nannocharax rubensteini
This is a tiny Congo Basin distichodontid that stays really small and has that sleek, "mini-darter" look. It tends to hang in the water column and pick at small foods, and it really shines in a calm, well-oxygenated setup with plenty of cover and a small group of its own kind.
Ruitoque pencil catfish
Trichomycterus ruitoquensis
This is a tiny Colombian Trichomycterus (a pencil catfish) from cool, upland streams in the Magdalena basin. It is the kind of skinny, bottom-hugging little catfish that spends its time nosing around rocks and crevices, and its wild range is super localized around the upper Lebrija drainage.
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Rummy-nose tetra
Petitella rhodostoma (syn. Hemigrammus rhodostomus)
This is the classic rummy-nose tetra - silver body, a solid red "face," and that crisp black-and-white tail that flashes when the whole group turns at once. The red nose is a legit mood ring for water quality and stress, so when they are happy and stable, they look incredible in a tight school.
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Rummy-nose tetra
Petitella rhodostoma (Ahl, 1924) (formerly Hemigrammus rhodostomus)
This is the classic rummy-nose tetra-the one with the bright red "nose" and the crisp black-and-white tail that flashes when the whole group turns together. They're tight-schoolers, so a bigger group in a longer tank is where you really get that synchronized, hypnotic swimming. The red face also doubles as a little "health meter" since it tends to fade when they're stressed or water quality slips.
Saadi dwarf stone loach
Turcinoemacheilus saadii
This is a little Iranian stone loach that lives glued to the bottom in fast, rocky streams, kinda like a tiny current-loving goby-but its a loach. The body has 7-9 dark saddle-shaped bands instead of a solid stripe, and it is built for scooting around coarse gravel and boulders in strong flow. Its not really an aquarium trade fish, but if you ever did keep one, you would set it up like a mini river tank with tons of oxygen and current.
Saikai grenadier (rattail)
Ventrifossa saikaiensis
This is a deepwater grenadier (rattail) from the western Pacific - the kind of fish that lives way down on the slope where its "aquarium" is basically cold, dark, and high pressure. It tops out around 25 cm and has that classic rattail look with a chin barbel, plus a ventral light organ. Cool animal, but realistically its not an aquarium species at all unless youre talking public-aquarium level coldwater deep-sea systems.
Salt and pepper cory (Habrosus cory)
Corydoras habrosus
This is the tiny "salt and pepper" cory that scoots around the bottom like a little wind-up toy, constantly sifting and picking through the sand. Keep them in a real group and they get way bolder-lots of quick little dashes, little pauses, and then back to foraging. They're also one of those fish that really rewards a soft sandy bottom and calm tankmates.
Samanti loach
Oxynoemacheilus seyhanensis
Oxynoemacheilus seyhanensis is a small Turkish brook loach from the Seyhan river system area - a bottom-hugger that wants clean, oxygen-rich water and lots of cover down low. In the wild it is a river fish and it's listed as Critically Endangered, so its real "cool factor" is more about being a rare, localized species than something you'll reliably see for sale.