Fish That Start With R
Browse all aquarium fish species with common names beginning with "R". Each profile includes care requirements, water parameters, tank size recommendations, and compatibility information for freshwater, marine, and brackish species.
Welcome to the species index for the letter 'R', where you will find a unique variety of aquarium fish. One highlight is the White-cheeked goby (Rhinogobius duospilus), a fascinating species known for its adaptability and charm. While this letter features a limited selection, it showcases intriguing options for both community aquariums and specialized habitats.
Raconda
Raconda russeliana
This is a slim, silvery pristigasterid herring with that long, flowing anal fin and a sharp belly keel - it is built to cruise open water. It is mostly a coastal marine fish but it shows up a lot in estuaries too, where it hunts tiny shrimp and other zooplankton-y stuff. Not really an aquarium species (way too pelagic and finicky), but it is a neat one to recognize when you are looking at Indian Ocean/far-west Pacific coastal fish lists.
Radiated puffer
Takifugu radiatus
Takifugu radiatus is a temperate, demersal marine puffer from the Northwest Pacific (Kyushu, Japan to the East China Sea) reaching about 20 cm standard length.
Rainford's goby
Koumansetta rainfordi
This little goby is a tiny striped hoverer that spends its day scooting between rock crevices and pecking at the sand and micro-stuff on the rocks. In the right setup its a super chill, reef-safe character fish, but the big trick is keeping it well-fed in a mature tank so it doesnt slowly waste away.
Ram cichlid (German blue ram / butterfly cichlid)
Mikrogeophagus ramirezi
Rams are tiny little cichlids with big-time attitude (in the cutest way) and insane sparkle-those blues, yellows, and that black face bar really pop when they're happy. They're also one of the warmer-water dwarf cichlids, and they'll show off pair behavior and even spawn on flat stones if you keep the tank clean and calm.
Randall’s shrimp goby
Amblyeleotris randalli
Randall's shrimp goby is that little candy-cane striped goby you'll see parked at the entrance of a burrow, doing sentry duty like it's getting paid for it. The really fun part is the partnership with a pistol shrimp-goby keeps watch, shrimp does the digging, and they basically run a tiny construction site in your sand bed. Give it a cozy sand area and a few rubble bits and it'll settle in and start acting like it owns the place (in the cutest way).
Red Neon Blue-eye (Luminatus Blue-eye)
Pseudomugil luminatus
This little blue-eye is basically a tiny fireworks show-males flash electric blue eyes and red/orange fins and spend half the day showing off to each other. Keep them in a nice-sized group and you'll see constant "dancing" and fin-flaring in the open water, especially over dark substrate and plants.
Red-lipped Wallaceochromis
Wallaceochromis rubrolabiatus
This is a tiny West African river cichlid that stays around 2.5 inches, and the adults get that really neat reddish-purple color around the lips that gives it its name. In a tank it acts more like a shy little cave cichlid than a bruiser - give it sand, leaf litter, and a couple tight caves and it settles in and starts doing the whole pair-bond and territory routine.
Redbanded seabream
Pagrus auriga
This is a big, chunky seabream that cruises rocky and rubble bottoms and eats crunchy stuff like crabs, shrimp, and mollusks. Super cool fish in the wild, but it gets way too large and boisterous for normal home aquariums - it is really more of a public-display kind of fish.
Redlips Darter
Etheostoma maydeni
This is a tiny Cumberland River drainage darter with a really neat telltale feature: the red pigment right on the lips. Its whole vibe is hanging out on the bottom in calmer pools along big creeks and rivers, tucked around boulders and woody cover.
Redsaddled snake eel
Quassiremus nothochir
This is a big, sand-loving snake eel from the eastern Pacific that spends a lot of its time tucked into the bottom with just the head showing. The cream-and-tan body with those dark-edged reddish saddle marks is the giveaway, and it is built for backing into the sand fast when it feels spooked. Cool animal, but realistically more of a public-aquarium fish than a home-tank project because of size and escape-artist vibes.
Redspotted snakehead
Channa andrao
Channa andrao is one of those "how is this real?" dwarf snakeheads-tiny, super colorful, and way more personable than you'd expect from a predator. It's a mouthbrooder, hangs near the surface a lot (air-breather), and it's happiest in a plant-choked, hidey-hole setup with a tight-fitting lid because, yep, it can jump.
Regan's dwarf pike cichlid
Wallaciia regani
This is one of the smaller pike cichlids, with that sleek, torpedo shape and the attitude to match - super fun to watch when it cruises and "stalks" around wood and leaf litter. It's a cave-spawning little predator that will absolutely snack on tiny fish, but compared to big pikes its size it can be surprisingly manageable if you give it space and lots of cover.
Reticulate clingfish
Tomicodon lavettsmithi
This is a tiny little clingfish from the NW Caribbean that spends its life plastered to rubble and shells in super-shallow water. It has that classic clingfish suction disc, so it can hang on in surge and pick at small prey right on the bottom. Not really a "community tank" fish - its whole vibe is cryptic, rock-hugging micro-predator in a saltwater nano.
Reticulate round ray
Urotrygon reticulata
A small, demersal round ray endemic to the Gulf of Panama that inhabits shallow sandy bottoms. Like other stingrays it has a venomous tail spine, and it is assessed as Critically Endangered (IUCN, assessed 24 Jan 2020), so it should not be targeted for aquarium trade.
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.
Rikuzen flounder
Dexistes rikuzenius
Dexistes rikuzenius is a right-eyed flounder from Japan and Korea that spends its life glued to the bottom, half-buried in sand or mud waiting to pounce on little critters. It is a cold-to-cool temperate, deeper-water flatfish (roughly 42-200 m) and not really an aquarium species unless you are set up for a chilled marine predator tank with a soft sandy bed.
River garfish (halfbeak)
Zenarchopterus clarus
Zenarchopterus clarus is a true halfbeak - that long lower jaw is built for picking stuff off the surface. Its a tropical, surface-cruising fish from the Western Central Pacific (Thailand and Borneo), and it reproduces via internal fertilization with ovoviviparous young.
Robust assfish
Bassozetus robustus
Bassozetus robustus (robust assfish) is a deep-sea marine cusk-eel (Ophidiidae) with a circumglobal distribution in tropical to temperate waters. It occurs at great depths (reported to >1000 m and to over 4000 m). Reproduction is oviparous and has been described as producing buoyant/pelagic eggs (reported as occurring in a gelatinous egg mass in some references). It is not an aquarium species, as its habitat conditions (depth/pressure and deep-sea environment) cannot be replicated in typical home systems.
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.
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.
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.
Roundtail duckbill
Bembrops greyi
The roundtail duckbill (Bembrops greyae) has the classic duckbill appearance with its broad, flattened head and a mouth designed for catching prey. Its natural home is way down on the slope, so its care is basically "public-aquarium only" rather than something that realistically fits a normal home setup.
Royal gramma
Gramma loreto
Royal grammas are that classic purple-to-yellow Caribbean basslet that likes to claim a cave and hover around it (sometimes totally upside-down under a ledge). They're usually chill with tankmates, but they can get spicy with other grammas/basslets/dottybacks if space is tight-give them rockwork and a "home" cave and they settle right in.