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
Ocellaris clownfish
Amphiprion ocellaris
Ocellaris clowns are that classic orange clownfish look-three white bars, a little black edging, and a ton of attitude packed into a small fish. They'll "pick a spot" in the tank (often a corner or a coral) and do that cute hover-wiggle thing, and a bonded pair will usually settle in fast and act like they own the place.
Ochre-banded goatfish
Upeneus sundaicus
A sand-sifting goatfish with bright yellow barbels and faint ochre bands on the tail. It cruises the bottom in small groups, using those whisker-like barbels to root out worms and tiny crustaceans, so it needs a big tank with fine sand and lots of meaty feedings.
Ocular coralblenny
Ecsenius oculatus
Ecsenius oculatus is a tiny little reef-percher from the Christmas Island/Western Australia area that spends its day scooting between holes and ledges and watching you like it owns the place. It is an algae-and-film grazer by nature, so in a mature reef it will constantly pick at rocks and glass and do that classic blenny hover-and-hop routine.
Okhotsk Hookear Sculpin
Artediellus ochotensis
A tiny coldwater sculpin from the Okhotsk and Bering side of the North Pacific, it spends life parked on the bottom waiting to pounce on snacks. The hooked spine on the gill cover gives it a tough look, and it perches and scoots around rocks with a lot of personality for such a small fish.
Oluolus hatchetfish
Polyipnus oluolus
Polyipnus oluolus is a tiny deepwater marine hatchetfish from the Marshall Islands that lives out in the open ocean and uses little light organs (photophores) on its body for camouflage and signaling in the dim water. It is super cool from a biology standpoint, but its pelagic deep-sea lifestyle makes it basically a non-aquarium species for normal hobby setups.
Oman snake eel
Yirrkala omanensis
This is a little snake eel from the Gulf of Oman that lives down on the bottom and does the classic eel thing - hiding/burrowing and staying out of sight most of the time. Its not really an aquarium-trade species, and most of what we know is from scientific collection records rather than hobby care notes. If you ever did try one, think secure lid and a sand-friendly setup, because ophichthids are basically born escape artists and diggers.
Orange bellowfish
Notopogon fernandezianus
Notopogon fernandezianus, the Orange bellowfish, is a bathydemersal bellowsfish occurring on the continental shelf and slope at 150–580 m in the Southeast Pacific (Juan Fernández–Nazca Ridge–Sala y Gómez, Chile) and the Southwest Atlantic (southern Brazil to Argentina). Temperatures in its range are cold (~11–17 °C). Its specialized deep‑cold habitat makes it unsuitable for typical home aquaria.
Orange-spotted toadfish
Torquigener hypselogeneion
This is a small Indo-west Pacific puffer that hangs around sandy flats and estuaries, and it will literally bury itself in the sand to nap with just the eyes sticking out. Its cheek bars and orange-yellow spotting make it look like a little camo tank. Cool fish to read about, but its pufferfish teeth and potential toxicity mean its not a typical community-aquarium pet.
Oriental bluespotted maskray
Neotrygon orientalis
Neotrygon orientalis is a smallish bluespotted maskray from the Indo-Malay/Philippines region - a bottom-hugging marine ray that cruises sandy areas and reefy flats. Its disk is sprinkled with blue spots and it has that classic "mask" marking around the eyes, but its real "wow" factor is how much space and clean sand it needs to live well. This is one of those animals that gets mislabeled as "a stingray for big home tanks" when it really belongs in public-aquarium-level setups.
Pacific bluestripe pipefish
Doryrhamphus melanopleura
This is one of the little flagtail pipefish with the long snout and that flashy tail fan with orange spots. In a calm reef tank it tends to hover around rock crevices and pick at tiny prey all day, so it is a super cool fish to watch - but it really needs gentle tankmates and frequent small meaty foods.
Pacific rock sole
Lepidopsetta bilineata
This is a cold-water right-eyed flatfish from the North Pacific that lives on sand-and-gravel bottoms and tops out around 2 feet. It is a bottom-hugging predator that munches worms, crustaceans, and other benthic critters, and it is really more of a public-aquarium/sea pen kind of animal than a home-tank fish.
Pacific sharpchin flyingfish
Fodiator rostratus
A sleek Eastern Pacific flyingfish that skims the surface on big pectoral "wings" and a pointy lower jaw. It is a super fast, open-water planktivore that will rocket right out of a tank, so it really needs public-aquarium scale water and a rock-solid lid. Watching them cruise the surface and burst into glide mode is wild.