Search Species
Search for fish species by common or scientific name, or use filters to browse by water type, size, temperament, and difficulty.
Found 562 species
Silverbelly cardinalfish
Jaydia photogaster
Jaydia photogaster is a small, nocturnal cardinalfish from the western Pacific that hangs around deeper lagoon patch reefs and tends to be seen solo or in little loose groups. The really neat bit is the silvery belly light-organ system (hence the name) and the subtle dusky bars down the sides - it is one of those understated fish that looks way cooler the longer you stare at it.
Similis annual killifish
Simpsonichthys similis
Simpsonichthys similis is a small Brazilian annual killifish from temporary pools in the São Francisco River basin. Like other annual rivulids, it spawns in the substrate; the eggs develop in a dry medium (diapause) and hatch on re-wetting. Adults are small (roughly 3–6 cm), and the species is best handled as a short-lived, breeding-focused project.
Singapore glassy perchlet
Ambassis kopsii
Ambassis kopsii is one of those cool little see-through mangrove/estuary fish that likes to hang out in a tight group, flashing silver in the light. It naturally lives where fresh and saltwater mix, so it does best when you treat it like a calm, slightly brackish schooling fish and give it lots of friends.
Sixline Wrasse
Pseudocheilinus hexataenia
The Sixline Wrasse is that nonstop little reef torpedo that weaves through rockwork all day hunting tiny critters. It's awesome for picking at pests like small worms/flatworms, but once it settles in it can get pretty territorial-especially in smaller tanks or with similar-shaped fish.
Sixstrap grubfish
Parapercis sexlorata
This is a little sandperch (grubfish) from eastern Australia that hangs around the bottom and blends in with sand and rubble. It is one of those fish that mostly sits and watches, then darts in for meaty food, and it can be a bit of a character in a marine setup. Also worth knowing: it is a deeper-water trawl species (about 86-137 m), so it is not really a typical warm-shallow reef fish.
Skunk loach
Yasuhikotakia morleti
This is the little loach with the bold black "skunk stripe" down its back, and it acts just as sassy as it looks. Give it a group and a pile of caves and it turns into a busy, clicking, bottom-patrolling gremlin that will happily hunt snails. It stays fairly small, but it can get nippy if you try to keep just one or you pair it with slow, long-finned fish.
Slate cory
Hoplisoma concolor
Corydoras concolor is that deep slate-gray, chunky little cory that looks almost like a moody, high-backed cousin of the bronze cory. Give them a soft sand bottom and a group to hang with, and you will see those neat rusty-orange fin flashes when they are comfortable. They are bottom cruisers that spend all day sifting and snuffling for food, and they will dart up for air now and then (totally normal).
Slender abyssal cusk-eel
Sciadonus pedicellaris
Sciadonus pedicellaris is a rare deep-sea livebearing brotula (family Bythitidae) with a very slender body, small deep-set eyes, and loose translucent skin; it occurs at bathyal to abyssal depths and is not suited to typical aquarium care. The name refers to the stalk-like (“pedicellate”) pectoral-fin base.
Slender lightfish
Vinciguerria attenuata
This is a tiny deep-water lightfish that spends its life way out in the ocean twilight zone, cruising up and down the water column each day. It has rows of photophores (little light organs) on the underside, plus those slightly tubular eyes that are built for looking up in the dark. Super cool biology, but realistically its not an aquarium fish at all.
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-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.
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.