Search Species
Search for fish species by common or scientific name, or use filters to browse by water type, size, temperament, and difficulty.
Found 337 species
Reticulated hillstream loach
Sewellia lineolata
This is the little "stingray-shaped" loach that parks itself on rocks and glass like it's magnetized, then cruises around in the current like a tiny river skate. Give it cool, super-oxygenated, fast-moving water and lots of smooth stones with biofilm, and it'll spend all day grazing and doing hilarious little dominance shuffles with its own kind.
Rosen's Hybrid Platy
Xiphophorus roseni
Xiphophorus roseni is a Mexican livebearer that shows up in the hobby mostly as a "weird/obscure Xiphophorus" rather than a mainstream platy or swordtail. The big twist is that a lot of sources treat it as a natural hybrid form (often discussed as variatus x couchianus), so it is more of a "locality oddball" than a clearly distinct, widely traded species.
Rosy Tetra
Hyphessobrycon bentosi
Rosy tetras are those little coppery-pink characins that look kinda "glowy" when the light hits them right, and the males can get nice extended fins when they're settled in. Keep a small group and you'll see them do their little pecking-order sparring and flashing-nothing scary, just classic tetra drama that looks awesome in a planted tank.
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.
Salsbury's osteochilus
Osteochilus salsburyi
Think of this one as a sleek silver river barb with a subtle mid-body stripe from Laos, northern Vietnam, and southern China. It spends its day rasping algae and biofilm off rocks and wood, so it appreciates good flow and clean water. It gets close to 8 inches, so plan real swimming room and ideally keep a small group.
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.