Search Species
Search for fish species by common or scientific name, or use filters to browse by water type, size, temperament, and difficulty.
Found 528 species
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.
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.
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.
Jordan's cod
Gadella jordani
This is a deep-water morid cod from the western Pacific that hangs out way down on the continental slope, hundreds of meters below the surface. It reaches about 28 cm and even carries a little luminous organ on its belly. Super interesting fish to learn about, but it is not a home aquarium candidate.
Kanazawa sand lance
Ammodytoides kanazawai
Think of a tiny silver dart that lives to dive into sand - that is this little sand-burrowing planktivore from Japan’s Ogasawara Islands. It tops out around 6.3 cm and was described in 2013 from a specimen trawled at roughly 95-99 m off Chichijima, so you pretty much never see it in home aquariums. Neat fish to read about, but best left in the ocean unless you run a serious marine setup with open water and fine sand for it to rocket into. ([fishbase.se](https://fishbase.se/summary/Ammodytoides-kanazawai.html))
Kazunagi
Zoarchias veneficus
A tiny eel-like prickleback from Japans cool rocky shores, it threads through seaweed and crevices like a living shoelace. Tops out around 7 cm and spends its time peeking from rock cracks and snapping up tiny crustaceans, so a tank full of snug caves is its happy place.
Keeltail pomfret
Taractes rubescens
Keeltail pomfret is a sleek open-ocean hunter with a sharp white crescent on the tail and a bony keel at the tail base that no other pomfret has. It gets big and cruises from near-surface to deep water, so it is one to admire in the wild rather than try to keep at home.
Kelp gunnel
Ulvicola sanctaerosae
This is a skinny little kelp-forest perch that literally hangs out up in the kelp canopy and chills on the fronds. One of the coolest bits is how it uses its tail to wrap onto kelp like a grip, then picks off tiny crustaceans drifting by. Not really an aquarium trade fish, but its a super neat West Coast oddball if you ever see one while diving.
Kerala sole
Zebrias keralensis
This is a small, sand-hugging marine sole from the Kerala coast area, with that classic zebra-style banding that helps it vanish the second it settles onto the bottom. Its whole deal is staying low, burying in fine sand, and picking off tiny bottom critters - super cool fish, but not really something you see in the aquarium trade.
Kermadec dwarfgoby
Eviota kermadecensis
This is a true micro-goby from the Kermadec Islands (Raoul Island area) - the kind of tiny reef fish that basically lives in the nooks and crannies and makes you stare at your rockwork more. Its whole vibe is cryptic and subtle, but that is exactly why dwarfgobies are so addicting once you start noticing them.
Kimura's sole
Aseraggodes kimurai
Aseraggodes kimurai is a tiny little marine sole (flatfish) from the western Pacific that spends its life glued to the bottom, blending into sand and rubble like a living leaf. Its whole vibe is stealth and camouflage, and it is the kind of fish you forget is even there until it scoots and re-buries itself. Super cool animal, but honestly not really an aquarium fish because it is a specialized bottom-dweller that wants live micro-food and a mature sandbed.