Search Species
Search for fish species by common or scientific name, or use filters to browse by water type, size, temperament, and difficulty.
Found 563 species
Slender mudskipper
Zappa confluentus
This is a tiny New Guinea mudskipper that lives around tidal mudflats by murky, brackish river water, and it can do the classic mudskipper trick of air-breathing when it is out of the water. In aquarium terms, think of it less like a regular "fish" and more like a little amphibious goby that wants a land area, lots of damp mud/sand to perch on, and calm brackish conditions.
Slender sunfish
Ranzania laevis
This is the little, weird cousin of the big ocean sunfishes - kind of an oval, squished-looking pelagic fish that literally loses the normal tail fin as it grows and ends up with a clavus instead. It cruises open water in warm-temperate to tropical seas, usually solo, picking off zooplankton and other small drifting prey.
Slender-tail golden-line barbel
Sinocyclocheilus gracilicaudatus
A small cave fish from the Pearl River karst in Guangxi, this one actually has normal eyes and a skinny tail, so it does not look as alien as its horned cousins. It likes cool, dark, very steady water and will cruise along the walls with that classic cavefish wall-following behavior once it settles in.
Slime skate
Dipturus pullopunctatus
This is a South African deep-water skate that lives way out on the shelf/upper slope, not something that belongs anywhere near a home aquarium. It gets big (around 1.3 m max reported) and is a bottom-dwelling predator, so it needs cold, high-oxygen marine conditions and huge space to swim and rest properly.
Small lanternfish
Diaphus roei
Diaphus roei is a tiny deep-sea lanternfish (a myctophid) that lives out in open ocean water and uses rows of photophores (light organs) for camouflage and communication. It is not really an aquarium species - it is a mesopelagic fish adapted to cold, high-pressure life and many individuals migrate upward at night.
Small Yunnan loach
Yunnanilus parvus
This is a tiny little stone loach from Yunnan, China that was originally described from a cave outlet - so think shady, cooler, clean water vibes. Its a bottom-hugging micro-loach that will spend a lot of time picking at the substrate for tiny bits of food, and its one of those species thats way more interesting to watch than its size suggests.
Smooth bandfish
Owstonia psilos
Owstonia psilos is a deepwater bandfish from off northwestern Australia - long, ribbon-bodied, reddish, and it has that neat black blotch up front on the dorsal fin. Its home turf is way down around 360-446 m, so its "cool factor" is real, but its natural lifestyle is totally a deep-reef, low-light thing rather than a normal home-aquarium fish.
South American Bumblebee Catfish
Microglanis parahybae
Microglanis parahybae is one of the little South American bumblebee catfish - a small, nocturnal bottom-dweller that spends the day wedged under wood, rocks, or leaf litter and comes alive at feeding time. They are peaceful with most community fish, but anything tiny enough to fit in that catfish mouth can disappear after lights-out.
Southern banded guitarfish
Zapteryx xyster
This is a little guitarfish from the tropical eastern Pacific that cruises sandy and rocky bottoms and comes out more at night to hunt. The coolest thing on adults is the yellow ocelli (eyespots) sitting in the dark bands across the back - it looks like someone dotted it with paint. It is a true saltwater ray-like elasmobranch, so think big footprint, lots of sand, and a heavy meaty diet.
Southern cardinalfish
Vincentia conspersa
This is a cool little temperate Aussie cardinalfish that spends the day tucked into caves and reef cracks, then comes out at night to hunt tiny crustaceans. The really neat part is breeding behavior - the male mouthbroods the eggs, so if you ever get a pair to spawn you will see him holding a big egg mass in his mouth for a while. Its a marine fish from southern Australia, so think "cooler reef tank" rather than a tropical reef setup.
Southern lightfish
Ichthyococcus australis
This is a deep-ocean little lightfish that lives way down in the dark and uses photophores (tiny light organs) for camouflage and signaling. It is a pelagic marine species from the southern hemisphere, and its whole vibe is "midwater stealth" rather than anything you would ever keep like a normal aquarium fish.
Southern mountain swordtail
Xiphophorus monticolus
Xiphophorus monticolus is a small, wild-type swordtail from Mexico that tends to hang in deeper pools in fast headwater streams with rocks and riffles. Males show a slender sword with darker edging and faint orange striping that can fade as they age, so its charm is more subtle than the gaudy domestic swordtail strains. Its big "gotcha" is that it is not a generic warm, hard-water livebearer - it comes from cooler, cleaner, flowing habitats, so it appreciates lots of oxygen and good maintenance.