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
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 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.
Southern platyfish
Xiphophorus maculatus
This is the classic platy-the little livebearer that's been bred into a ridiculous number of colors, but the wild-type is more of an olive-brown fish with dark blotches. They're super active, always cruising for snacks, and you'll see fun social behavior when you keep them in a small group. Also: if you mix males and females, you'll almost certainly end up with fry-these guys don't waste any time.
Southwell's pipefish
Siokunichthys southwelli
A tiny tropical marine pipefish from Sri Lanka and the Philippines. Like many syngnathids, it is a slow, deliberate feeder that may require abundant small live foods and low-competition tankmates in captivity.
Speckled butterfly loach
Beaufortia polylepis
Beaufortia polylepis is one of those little hillstream loaches that looks like a tiny freshwater stingray with a speckled pattern, and it spends its day suctioned onto rocks grazing biofilm. The big trick with them is not "special water" so much as lots of oxygen and brisk flow - think cool, clean stream vibes, not a warm, still community tank.
Speckled goby
Redigobius isognathus
A tiny estuary goby with a neat checkered body pattern and a surprisingly big mouth for such a small fish. It hangs out on the bottom, scooting between shells and rocks, and will happily pick at tiny crustaceans and other bite-size foods. Folks sometimes confuse it with the similar R. bikolanus, and it does great in lightly brackish setups with hard, alkaline water.
Spikefin goby
Discordipinna griessingeri
This is that tiny little reef goby with the crazy tall first dorsal spines and orange striping that makes it look like a living piece of candy. It spends a lot of time tucked into coral rubble and little crevices, then darts out to grab food, so giving it real hiding spots is the whole game. Also, it gets mixed up in the trade with the wrong name sometimes, so its worth double-checking the label before you buy.
Spinach pipefish
Microphis spinachioides
This is a freshwater pipefish from Papua New Guinea - basically a tiny river cousin of seahorses with that stiff, armored "stick" body and a little tube snout for picking off micro-crustaceans. The really wild part is the males brood the eggs, and the species is so rarely seen in the wild that a lot of info we normally lean on for aquarium care just straight-up is not documented.
Spinaker grenadier
Ventrifossa nigrodorsalis
This is a deep-sea rattail (grenadier) from the continental slope - long, tapering body, chin barbel, and that cool dark blotch on the first dorsal fin. Its natural home is hundreds of meters down, so its needs are basically the opposite of a typical home aquarium: cold, dark, very high pressure habitat, and a life built around picking off fish and squid in the deep.
Spindle Yunnan loach
Yunnanilus elakatis
Yunnanilus elakatis is a nemacheilid (stone loach) endemic to Yunnan, China (type locality: Yiliang County). Aquarium-specific husbandry data for this exact species is scarce in major references; when kept, it should be maintained like other small stream-associated stone loaches: high water quality, good oxygenation, and a fine, smooth substrate with cover.