Fish That Start With J
Browse all aquarium fish species with common names beginning with "J". Each profile includes care requirements, water parameters, tank size recommendations, and compatibility information for freshwater, marine, and brackish species.
The letter 'J' features a diverse range of aquarium species, including popular community fish like the American flagfish (Jordanella floridae) and the visually striking Golden Julie (Julidochromis ornatus). Enthusiasts will also find unique fish such as Hung's silvermouth cardinalfish (Jaydia hungi) and the Masked julie (Julidochromis transcriptus), each adding their own charm to aquariums. Explore these species to find the perfect addition for your aquatic display.
Jacunda
Wallaciia notophthalmus
This is a little dwarf pike cichlid from the Rio Negro area - small body, big attitude, and it loves to claim a cave. Males get those cool long, pointed first dorsal-fin rays, and when they pair up they do real cichlid-style parenting (cave spawning and guarding).
Jadova minnow
Delminichthys jadovensis
This is a tiny karst-stream minnow that lives in just a sliver of Croatia, and it actually ducks into subterranean waters (or hides in mud) when conditions get rough. Its whole life is tied to super clear, slow-flowing streams, so it is more of a conservation fish than something you will realistically see for sale.
Jaguar livebearer
Jenynsia onca
Jenynsia onca is an unusual anablepid livebearer often called a one-sided livebearer; males have an asymmetrical gonopodium and mating may involve lateralized positioning (though some sources dispute strict left/right-only pairing). In aquaria they are active schooling fish that prefer cooler, well-oxygenated water and are best kept in groups.
Jalisco chub
Yuriria alta
Yuriria alta is a Mexican freshwater chub endemic to central Mexican basins (including the Lerma–Chapala region) reaching about 18.2 cm SL. The species is listed as Endangered (IUCN), so collection/keeping may be restricted and it is more often of conservation/biotope interest than a mainstream aquarium fish.
Japanese deepwater clingfish
Aspasma minima
Aspasma minima is a tiny little marine clingfish from southern Japan that spends its life hugging hard surfaces with that cool suction-disc belly. Its whole vibe is secretive and bottom-oriented, more like a micro predator you design a tank around than a "community fish" you toss in with everything.
Japanese dory
Zenion japonicum
Zenion japonicum is a small deepwater dory from way down on the continental slope - silvery, big-eyed, and kind of "alien-cute" in that zeiform way. This is not an aquarium fish in any normal sense (it lives hundreds of meters deep in cold water), but it is a really neat bycatch species with that classic dory shape and spiny fins.
Japanese scorpionfish
Rhinopias argoliba
Rhinopias argoliba is one of those sit-and-wait ambush predators that basically looks like a chunk of reef rubble until it decides to inhale something whole. Its claim to fame is that pale teardrop mark under the eye and the more "clean" look (fewer frilly appendages) compared to some other Rhinopias. Super cool fish, but you plan the whole stocking list around its mouth size and the fact it is a venomous scorpionfish.
Japanese silver-biddy
Gerres equulus
Gerres equulus (Japanese silver-biddy) is a temperate, demersal coastal mojarra from the northwest Pacific (southern Korea to southern Japan), typically over sandy shallows; it is generally reported as absent from the Ryukyu Islands. It is primarily a coastal fish and is not commonly maintained in home aquaria; if kept, provide ample open swimming space and stable marine conditions.
Japonoconger africanus
Japonoconger africanus
A deep-water conger eel from the eastern Atlantic (Gabon to Republic of the Congo), bathydemersal at roughly 250–650 m. Max length about 42.5 cm TL. Feeds on benthic fishes, shrimps, and crabs. Modeled preferred temperatures from occurrence data are ~3.8–5.9 °C, which together with its depth range makes it effectively unsuited to home aquaria; there is no established captive-care protocol.
Jewelled blenny
Salarias fasciatus
This is the classic "lawnmower" blenny - a little reef perch-fish that spends its day scooting around the rocks, scraping film algae and looking like it has tiny eyebrows. Give it a mature tank with lots of live rock to graze and it will stay busy all day, but if the tank is too clean it can slowly starve unless you supplement greens.
Jingxi Yunnan loach
Yunnanilus jinxiensis
This is a small Chinese stone loach from Guangxi, and its whole vibe is "hang out on the bottom and poke around". It comes from a pretty specific local area (Jingxi County), so you are not likely to see it in the regular aquarium trade. If you do run into one, think cool, clean, well-oxygenated water and lots of hiding spots like you would for other little nemacheilid loaches.
Johnston Island damsel
Plectroglyphidodon johnstonianus
This is one of those tough little reef damsels that acts like it owns the whole rock pile, especially once it settles in. Maxes out around 14 cm and will absolutely defend a favorite cave or coral head, but the blue eye and chunky "wide bar" look make it a really cool fish if you plan the tank around its attitude.
Johnston's Docimodus
Docimodus johnstoni
Docimodus johnstoni is one of those oddball Lake Malawi haps that makes you go "wait, it eats what?" In the wild its been reported nipping fins (especially on big catfish), so its a super interesting fish biologically but not a great community aquarium citizen.
Jonah's icefish
Neopagetopsis ionah
Jonah's icefish is a weird and wonderful Antarctic icefish that lives in near-freezing seawater on the continental shelf and slope. It is a predator that eats fish and krill, and it is famous for nest-building and egg-guarding behavior, including massive nesting colonies documented in the Weddell Sea.
Jonathan's cusk-eel
Neobythites jonathan
Neobythites jonathan is a deepwater cusk-eel from the western Pacific (Solomon Sea) that lives way down on the lower shelf/upper slope. It is a small, slender bottom-associated fish with a bold ocellus (eye-spot) on the dorsal fin - cool little bit of "fake eye" patterning you see in a bunch of Neobythites.
Jupiaba apenima
Jupiaba apenima
A tiny stream-loving tetra out of the upper Tapajos basin in Brazil, Jupiaba apenima is an active little shoaler that loves clean, moving water. It even has a neat forward-pointing pelvic spine, and there are Moenkhausia that mimic its look in the wild. Give it a soft, slightly acidic, well-oxygenated setup and a good-sized group and it will stay busy all day.
Jupiaba tetra
Jupiaba pinnata
Jupiaba pinnata is a small South American characin from the Guianas that stays around 5.8 cm standard length. Its vibe is very "tetra-like" - quick, active, and happiest when its kept in a proper group with open swimming space and some cover.
Jurubida ghost knifefish
Apteronotus jurubidae
Apteronotus jurubidae is a little Colombian ghost knifefish that cruises around using a weak electric field to "see" in the dark, and it can back up as easily as it goes forward. It is not something you will typically see in the aquarium trade, but it should behave a lot like other Apteronotus: shy by day, way more active at feeding time, and obsessed with having tight hiding spots.