Species
Browsing 1,911 species. Use the filters below to narrow down.
One-lined Pencilfish
FishNannostomus unifasciatus
A tiny pencilfish that swims at a permanent angle, day and night.
Oneline Tetra
FishNannaethiops unitaeniatus
A peaceful little African schooler that deserves far more attention than it gets.
One-spot Eartheater
FishSatanoperca lilith
A rarely traded eartheater with a single bold flank spot and surprising social depth.
One Spot Mouthbrooder
FishBetta unimaculata
A mouthbrooding Betta from Borneo that bucks the aggressive stereotype entirely.
Onespot Squeaker
FishSynodontis notata
A daytime-active catfish with a bold personality to match its bold spot.
One-stripe Anthias
FishPseudanthias fasciatus
A deep-reef anthias famous for swimming upside-down along cave ceilings.
One-stripe Spiny Eel
FishMacrognathus aculeatus
A serpentine burrower with a single bold stripe and a secretive personality.
Opsarius ardens
FishBarilius ardens
A fast-moving Western Ghats minnow that needs space, speed, and bold companions.
Oranda Goldfish
FishCarassius auratus var. oranda
The velvet-capped fancy goldfish that rewards patient, attentive keeping.
Orange Chromide
FishEtroplus maculatus
The only cichlid native to India, with a fascinating cleaning-fish side hustle.
Orange dwarf toothcarp
FishNeoheterandria elegans
A tiny Colombian livebearer with a fascinating near-mammalian reproductive twist.
Orangefin Anemonefish
FishAmphiprion chrysopterus
A large, bold anemonefish from the wide Pacific with serious territorial attitude.
Orange-fin Barb
FishBarbus eutaenia
A sleek African barb from fast, rocky streams that rewards patient keepers.
Orangefin Tetra
FishBryconops affinis
A restless, fast-moving shoaler from the Guiana Shield's coastal streams.
Orangeflossen
FishLaetacara fulvipinnis
A tiny blackwater cichlid with warm-toned fins and a gentle personality.
Orange Head
FishGeophagus sp. "Orange Head"
A vividly capped cichlid that rewards patient keepers with fascinating mouthbrooding family life.
Orangespine Unicornfish
FishNaso elegans
A bold reef grazer with vivid orange tail spines and a distinctly regal profile.
Orangespot Surgeonfish
FishAcanthurus olivaceus
A bold orange shoulder-stripe makes this reef surgeon impossible to mistake.
Orangestriped Triggerfish
FishBalistapus undulatus
One of the reef's most aggressive personalities packed into a boldly patterned body.
Orchid Dottyback
FishPseudochromis fridmani
A bold little Red Sea endemic that punches well above its weight.
Orchid Island Goby
FishRhinogobius lanyuensis
A tiny island goby from one of Taiwan's most remote corners.
Orinoco Eartheater
FishBiotodoma wavrini
A slender eartheater that thrives in groups and rewards patient, experienced keepers.
Orinoco sailfin catfish
FishPterygoplichthys multiradiatus
A dinosaur-sized algae grazer built for decades of service in large tanks.
Ornate Bichir
FishPolypterus ornatipinnis
An ancient, armored predator that breathes air and prowls the night.
Ornate Paradisefish
FishMalpulutta kretseri
A rare Sri Lankan gem that deserves a species tank all to itself.
Ornate rainbowfish
FishRhadinocentrus ornatus
A tiny Australian rainbowfish from wild, tea-stained wallum streams.
Oscar
FishAstronotus ocellatus
The cichlid that recognizes your face and rearranges its own tank.
Otocinclus
FishOtocinclus vittatus
Tiny algae-grazing catfish that plasters itself to glass and plants alike.
Otocinclus Catfish (Tank-Bred)
FishOtocinclus macrospilus
The most commonly sold oto, fragile at first but rewarding once settled.
Otocinclus cocama
FishA tiny Peruvian algae grazer with bold, zebra-like blotches and a gentle disposition.
Oyapock Cory
FishCorydoras condiscipulus
A long-lived Oyapock armored catfish that breathes air and blinks its eyes.
Oyapock Eartheater
FishGeophagus camopiensis
A rarely seen eartheater with elaborate mouthbrooding behavior and real personality.
Pacific Double-saddle Butterflyfish
FishChaetodon ulietensis
A boldly patterned butterflyfish that pairs for life in the wild.
Pacific Fat Sleeper
FishDormitator latifrons
A chunky estuarine predator that breathes air and swallows anything it can fit in its mouth.
Pacific Molly
FishPoecilia butleri
A personable little livebearer that grazes algae and practically eats from your hand.
Pacu
FishPiaractus mesopotamicus
A seed-crunching giant from South American floodplains that outgrows almost any home aquarium.