Search Species
Search for fish species by common or scientific name, or use filters to browse by water type, size, temperament, and difficulty.
Found 654 species
Blotched catshark
Scyliorhinus meadi
Scyliorhinus meadi is a deepwater little catshark from the western central Atlantic that hangs out way down on the continental slope around 300-600 m. It is got those dark saddle-like blotches and even has tiny spots that can fluoresce yellow under blue light, which is pretty wild for a shark. This is not really an aquarium fish - it is a cold, deepwater species with specialized needs and basically no normal hobby availability.
Blueband goby
Valenciennea strigata
This is that classic gold/yellow-headed sand-sifting goby with the little blue cheek stripe-always busy, always rearranging your sandbed. In a reef tank it'll spend the day taking mouthfuls of sand, filtering out tiny critters/foods, then "snowing" clean sand back out, and it'll usually claim a burrow area (often as a pair in the wild). It's super cool behavior-wise, but you really do need a mature tank with a proper sandbed and a lid because they can jump.
Blue blanquillo
Malacanthus latovittatus
This is the long, torpedo-shaped tilefish with the blue front end and that bold black stripe down the side. In the wild it hangs over outer reef slopes and will also claim a burrow area, so in a tank you are basically keeping a cruise-missile that also wants a safe "home base" and a tight lid.
Blue discus
Symphysodon aequifasciatus
This is one of the classic wild discus from the Amazon-big, round, and super "cichlid-smart," but way more chill than most cichlids. The coolest part to me is the parenting: the fry actually feed off a mucus layer from the parents' skin for a while, which is just wild to see if you ever breed them.
Blue dorsal Borneo sucker
Gastromyzon ctenocephalus
This is one of the little Borneo hillstream loaches that scoots around like a tiny living suction cup, spending most of its day grazing on biofilm off smooth rocks. The cool part is the fin patterning - the caudal fin has bold pale-blue striping, and they do those quick little territorial "flaring" displays with each other without usually doing real damage. Keep it in a high-oxygen, high-flow setup and it just settles in and does its thing.
Blue sheatfish
Kryptopterus cryptopterus
Think of this as the bigger, moodier cousin of the glass catfish. It hangs in the midwater in a loose group, ghosting along in the shade and coming alive at feeding time. Super chill with similar-sized fish, but it will snack on tiny tankmates if they fit in that wide mouth.
Blue skate
Notoraja azurea
Gorgeous fish, but strictly a look-dont-keep species: a metallic-blue deepwater skate from southern Australia that glides along the continental slope 765-1440 m down in about 3-6 C water. It tops out around 65 cm and occasionally turns up in deep-sea trawls, but conditions that cold and pressurized put it way outside home-aquarium territory. ([fishbase.se](https://fishbase.se/summary/SpeciesSummary.php?id=63978))
Blunt-snouted grenadier
Ventrifossa obtusirostris
This is a deep-sea rattail (grenadier) from the southeastern Pacific, living way down on the slope around 750-800 m deep. It is a long, tapering, big-headed macrourid that tops out around 30 cm, and its short, blunt snout is basically the whole idea behind the species name.
Bob Ward's bluespotted maskray
Neotrygon bobwardi
A bluespotted maskray (Neotrygon bobwardi) described as part of the former Neotrygon kuhlii species complex, reported from Indonesia in the eastern Indian Ocean (notably western Sumatra).
Boeseman's rainbowfish
Melanotaenia boesemani
Boesemani rainbows are basically little swimming fireworks once they settle in-males get that wild split-color look (blue up front, orange in back) and they'll flash and posture at each other all day. They're super active and way happier in a real group with a long tank to cruise, not a cramped setup where they can't stretch out.
Borari knodus tetra
Knodus borari
Knodus borari is a tiny, brand-new-to-science (described in 2023) little characin from Brazil's lower Rio Tapajos area. Its wild habitat is a moderately fast stream over rock-gravel-sand, so I'd treat it like an active small schooling tetra that appreciates clean, oxygen-rich water and some current.
Borneo sucker
Gastromyzon fasciatus
Gastromyzon fasciatus is one of those super-cool little Borneo hillstream loaches that scoots around rocks like a tiny stingray and parks itself in the current. It really shines in a river-style setup with lots of smooth stones to graze on and high oxygen - they look busy all day and have a neat, banded pattern.