There are 159 fish that start with the letter O, from Oarfish to Oxford Netted Dogfish. Below you will find them listed alphabetically along with some general information about each. Click the toggle view buttons in the top right corner to switch between the card and the table view.
For each item you will find the following information
Order: The subclass the fish belongs to
Habitat: The places or type of weather the fish lives in
Scientific name: The designation that scientists use to catalog the species
Name: Oarfish
Order: Lampriformes
Habitat: Deep Pelagic
Scientific name: Regalecus glesne
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Name: Oarfish (giant)
Order: Lampriformes
Habitat: Deep Pelagic
Scientific name: Regalecus russelii
Name: Oblique Cardinalfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Apogon obliquus
Name: Oblique Sweetlips
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Plectorhinchus macrolepis
Name: Oblique-banded Pipefish
Order: Syngnathiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Corythoichthys ocellatus
Name: Oblique-banded Seabream
Order: Perciformes
Habitat: Mediterranean Sea (coastal)
Scientific name: Oblada melanura
Name: Oblique-banded Snapper
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Lutjanus vitta
Name: Oblong Pipefish
Order: Syngnathiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Halicampus macrorhynchus
Name: Oblong Silver Biddy
Order: Perciformes
Habitat: Tropical Marine (coastal)
Scientific name: Gerres oblongus
Name: Oblong Snapper
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Lutjanus oblongus
Name: Oblong Sole
Order: Pleuronectiformes
Habitat: Tropical Marine (benthic)
Scientific name: Solea oblonga
Name: Oblong Sunfish
Order: Perciformes
Habitat: Freshwater (North America)
Scientific name: Enneacanthus elongatus
Name: Ocean Pout
Order: Perciformes
Habitat: Temperate Atlantic Ocean (benthic)
Scientific name: Macrozoarces americanus
Name: Ocean Sunfish
Order: Tetraodontiformes
Habitat: Pelagic (open ocean)
Scientific name: Mola mola
Name: Ocean Triggerfish
Order: Tetraodontiformes
Habitat: Pelagic (tropical and subtropical)
Scientific name: Canthidermis maculata
Name: Oceanic Bass
Order: Perciformes
Habitat: Deep Sea (Comoros Islands)
Scientific name: Latimeria chalumnae
Name: Oceanic Basslet
Order: Perciformes
Habitat: Deep Sea (benthic)
Scientific name: Hemanthias vivanus
Name: Oceanic Flyingfish
Order: Beloniformes
Habitat: Pelagic (tropical and subtropical)
Scientific name: Exocoetus volitans
Name: Oceanic Garfish
Order: Beloniformes
Habitat: Pelagic (tropical and subtropical)
Scientific name: Tylosurus acus
Name: Oceanic Sargo
Order: Perciformes
Habitat: Eastern Pacific (coastal)
Scientific name: Anisotremus interruptus
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Name: Oceanic Sunfish (Mola)
Order: Tetraodontiformes
Habitat: Pelagic (open ocean)
Scientific name: Mola mola
Name: Oceanic Tripod Fish
Order: Aulopiformes
Habitat: Deep Sea (benthic)
Scientific name: Bathymicrops regis
Name: Oceanic Whitetip Shark
Order: Carcharhiniformes
Habitat: Pelagic (tropical and subtropical)
Scientific name: Carcharhinus longimanus
Name: Ocellaris Clownfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Amphiprion ocellaris
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Name: Ocellate Moray (Gymnothorax ocellatus)
Order: Anguilliformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Gymnothorax ocellatus
Name: Ocellate Snapper
Order: Perciformes
Habitat: Western Atlantic (tropical)
Scientific name: Lutjanus campechanus
Name: Ocellated Barbfish
Order: Scorpaeniformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Scorpaena histrio
Name: Ocellated Barred Goby
Order: Gobiiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Priolepis nocturna
Name: Ocellated Dragonet
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Synchiropus ocellatus
Name: Ocellated Dragonfish
Order: Stomiiformes
Habitat: Deep Sea (pelagic)
Scientific name: Malacosteus niger
Name: Ocellated Flathead
Order: Scorpaeniformes
Habitat: Tropical Marine (benthic)
Scientific name: Platycephalus ocellatus
Name: Ocellated Flounder
Order: Pleuronectiformes
Habitat: Western Atlantic (benthic)
Scientific name: Ancylopsetta quadrocellata
Name: Ocellated Frogfish
Order: Lophiiformes
Habitat: Western Atlantic (tropical)
Scientific name: Antennarius ocellatus
Name: Ocellated Moray
Order: Anguilliformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Gymnothorax ocellatus
Name: Ocellated Pipefish
Order: Syngnathiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Corythoichthys ocellatus
Name: Ocellated Razorfish
Order: Perciformes
Habitat: Tropical Marine (sandy bottoms)
Scientific name: Xyrichtys novacula
Name: Ocellated Sand Diver
Order: Perciformes
Habitat: Western Atlantic (sandy bottoms)
Scientific name: Synodus ocellaris
Name: Ocellated Scorpionfish
Order: Scorpaeniformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Scorpaenopsis neglecta
Name: Ocellated Skate
Order: Rajiformes
Habitat: Temperate Atlantic (benthic)
Scientific name: Raja ocellata
Name: Ocellated Snake Eel
Order: Anguilliformes
Habitat: Tropical Marine (sandy bottoms)
Scientific name: Ophichthus ocellatus
Name: Ocellated Stargazer
Order: Perciformes
Habitat: Tropical Marine (benthic)
Scientific name: Gnathagnus cribratus
Name: Ocellated Toby
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Canthigaster ocellicincta
Name: Ocellated Velvetfish
Order: Scorpaeniformes
Habitat: Indo-Pacific (benthic)
Scientific name: Anema ocellata
Name: Ocellated Wrasse
Order: Perciformes
Habitat: Mediterranean Sea (rocky reefs)
Scientific name: Symphodus ocellatus
Name: Octopusfish
Order: Scorpaeniformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Scorpaenopsis venosa
Name: Odd Gurnard
Order: Scorpaeniformes
Habitat: Deep Sea (benthic)
Scientific name: Satyrichthys rieffeli
Name: Ogilby's Wrasse
Order: Perciformes
Habitat: Mediterranean Sea (rocky reefs)
Scientific name: Symphodus rostratus
Name: Oilfish
Order: Perciformes
Habitat: Deep Pelagic (tropical and temperate waters)
Scientific name: Ruvettus pretiosus
Name: Okhotsk Atka Mackerel
Order: Scorpaeniformes
Habitat: Temperate North Pacific (benthic)
Scientific name: Pleurogrammus azonus
Name: Old English Sheepdog Wrasse
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Halichoeres hortulanus
Name: Old Wife
Order: Perciformes
Habitat: Temperate Australian Marine (coastal reefs)
Scientific name: Enoplosus armatus
Name: Old Wife Cod
Order: Gadiformes
Habitat: Tropical Marine (deep water)
Scientific name: Bregmaceros macclellandi
Name: Olive Blenny
Order: Blenniiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Cirripectes castaneus
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Name: Olive Blenny (Hypsoblennius)
Order: Blenniiformes
Habitat: Eastern Pacific (rocky shores)
Scientific name: Hypsoblennius sordidus
Name: Olive Bonito
Order: Scombriformes
Habitat: Tropical Atlantic (pelagic)
Scientific name: Orcynopsis unicolor
Name: Olive Flounder
Order: Pleuronectiformes
Habitat: Temperate Pacific Ocean (benthic)
Scientific name: Paralichthys olivaceus
Name: Olive Rockfish
Order: Perciformes
Habitat: Temperate Pacific (rocky reefs)
Scientific name: Sebastes serranoides
Name: Olive Scorpionfish
Order: Scorpaeniformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Scorpaenopsis venosa
Name: Omani Sole
Order: Pleuronectiformes
Habitat: Tropical Marine (benthic)
Scientific name: Solea omanensis
Name: One Spot Cardinalfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Apogon unicolor
Name: One-spot Flasher Wrasse
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Paracheilinus octotaenia
Name: Onefin Catfish
Order: Siluriformes
Habitat: Freshwater (Africa)
Scientific name: Synodontis eupterus
Name: Onefin Flashlight Fish
Order: Myctophiformes
Habitat: Tropical Marine (deep reef)
Scientific name: Photoblepharon palpebratum
Name: Onefin Ghostfish
Order: Aulopiformes
Habitat: Pelagic (deep sea)
Scientific name: Anotopterus vorax
Name: Onion Brotula
Order: Ophidiiformes
Habitat: Deep Sea (benthic)
Scientific name: Brotula barbata
Name: Onionfish
Order: Perciformes
Habitat: Temperate Atlantic (benthic)
Scientific name: Ogcocephalus radiatus
Name: Opah
Order: Lampriformes
Habitat: Deep Pelagic (tropical and temperate waters)
Scientific name: Lampris guttatus
Name: Open Ocean Dolphin Fish
Order: Perciformes
Habitat: Pelagic (tropical and subtropical)
Scientific name: Coryphaena hippurus
Name: Opossum Pipefish
Order: Syngnathiformes
Habitat: Brackish/Freshwater (Indo-Pacific)
Scientific name: Microphis brachyurus
Name: Opposite-sex Pipefish
Order: Syngnathiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Corythoichthys paxtoni
Name: Orange Anemonefish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Amphiprion percula
Name: Orange Basslet
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Liopropoma carmabi
Name: Orange Blotch Hap
Order: Cichliformes
Habitat: Freshwater (Lake Malawi)
Scientific name: Maylandia callainos
Name: Orange Blotched Triggerfish
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Rhinecanthus verrucosus
Name: Orange Butterflyfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Chaetodon kleinii
Name: Orange Damsel
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Abudefduf vaigiensis
Name: Orange Goby
Order: Gobiiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Gobiodon citrinus
Name: Orange Razorfish
Order: Perciformes
Habitat: Tropical Marine (sandy bottoms)
Scientific name: Iniistius uwii
Name: Orange Roughy
Order: Beryciformes
Habitat: Deep Sea (benthic)
Scientific name: Hoplostethus atlanticus
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Name: Orange Roughy (juvenile)
Order: Beryciformes
Habitat: Deep Sea (pelagic to benthic)
Scientific name: Hoplostethus atlanticus
Name: Orange Skunk Clownfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Amphiprion akallopisos
Name: Orange Snapper
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Lutjanus fulvus
Name: Orange Spotted Blenny
Order: Blenniiformes
Habitat: Tropical Marine (rocky shores)
Scientific name: Istiblennius spilotus
Name: Orange Spotted Moray
Order: Anguilliformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Gymnothorax meleagris
Name: Orange Unicornfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Naso maculatus
Name: Orange-banded Coralfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Chaetodon ornatissimus
Name: Orange-barred Emperor
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Lethrinus kallopterus
Name: Orange-breasted Sunfish
Order: Perciformes
Habitat: Freshwater (North America)
Scientific name: Lepomis auritus
Name: Orange-dotted Tuskfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Choerodon anchorago
Name: Orange-fin Squirrelfish
Order: Beryciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Sargocentron cornutum
Name: Orange-lined Cardinalfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Apogon compressus
Name: Orange-lined Fairy Wrasse
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Cirrhilabrus lineatus
Name: Orange-lined Squirrelfish
Order: Beryciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Sargocentron rubrum
Name: Orange-lined Triggerfish
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Balistapus undulatus
Name: Orange-spotted Blenny
Order: Blenniiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Salarias fasciatus
Name: Orange-spotted Catshark
Order: Carcharhiniformes
Habitat: Tropical Marine (benthic)
Scientific name: Chiloscyllium plagiosum
Name: Orange-spotted Filefish
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Oxymonacanthus longirostris
Name: Orange-spotted Grouper
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Epinephelus coioides
Name: Orange-spotted Isoscelesfish
Order: Perciformes
Habitat: Temperate Marine (coastal)
Scientific name: Upeneichthys lineatus
Name: Orange-spotted Spinefoot
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Siganus guttatus
Name: Orange-spotted Trevally
Order: Carangiformes
Habitat: Tropical Marine (coastal)
Scientific name: Carangoides fulvoguttatus
Name: Orange-spotted Wrasse
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Bodianus opercularis
Name: Orange-striped Cardinalfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Apogon cyanosoma
Name: Orange-striped Triggerfish
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Sufflamen chrysopterum
Name: Orange-tipped Cardinalfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Apogon nigripes
Name: Orangeback Anglerfish
Order: Lophiiformes
Habitat: Temperate Atlantic (benthic)
Scientific name: Lophius americanus
Name: Orangeback Bass
Order: Perciformes
Habitat: Atlantic Ocean (benthic)
Scientific name: Serranus annularis
Name: Orangebanded Coralfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Chaetodon ornatissimus
Name: Orangechin Triggerfish
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Xanthichthys caeruleolineatus
Name: Orangefin Butterflyfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Chaetodon xanthurus
Name: Orangefin Piranha
Order: Characiformes
Habitat: Freshwater (South America)
Scientific name: Serrasalmus rhombeus
Name: Orangefin Surgeonfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Acanthurus auranticavus
Name: Orangehead Filefish
Order: Tetraodontiformes
Habitat: Tropical Marine (coastal)
Scientific name: Monacanthus hispidus
Name: Orangehead Hawkfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Paracirrhites arcatus
Name: Orangespine Squirrelfish
Order: Beryciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Sargocentron spiniferum
Name: Orangespine Unicornfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Naso lituratus
Name: Orangespot Surgeonfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Acanthurus olivaceus
Name: Orangespot Wrasse
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Halichoeres melanurus
Name: Orangestriped Goatfish
Order: Perciformes
Habitat: Tropical Marine (sandy bottoms)
Scientific name: Upeneus taeniopterus
Name: Orangethroat Darter
Order: Perciformes
Habitat: Freshwater (North America)
Scientific name: Etheostoma spectabile
Name: Orcaella Wrasses
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Cheilinus orans
Name: Orchard Goby
Order: Gobiiformes
Habitat: Freshwater (North America)
Scientific name: Ctenogobius sp.
Name: Orconaut
Order: Perciformes
Habitat: Tropical Marine (moray eel)
Scientific name: Gymnothorax ocellatus
Name: Oregon Chub
Order: Cypriniformes
Habitat: Freshwater (North America)
Scientific name: Oregonichthys crameri
Name: Oregon Spotted Frogfish
Order: Lophiiformes
Habitat: Eastern Pacific (benthic)
Scientific name: Antennarius pardalis
Name: Oriental Flying Gurnard
Order: Scorpaeniformes
Habitat: Tropical Marine (sandy bottoms)
Scientific name: Dactyloptena orientalis
Name: Oriental Sweetlips
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Plectorhinchus vittatus
Name: Ornate Anglerfish
Order: Lophiiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Antennarius commerson
Name: Ornate Boxfish
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Ostracanthus ornatissimus
Name: Ornate Butterflyfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Chaetodon reticulatus
Name: Ornate Coralfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Coradion ornatissimus
Name: Ornate Flounder
Order: Pleuronectiformes
Habitat: Temperate Marine (benthic)
Scientific name: Arnoglossus armstrongi
Name: Ornate Frogfish
Order: Lophiiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Antennarius pictus
Name: Ornate Ghost Pipefish
Order: Syngnathiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Solenostomus paradoxus
Name: Ornate Leatherjacket
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Amanses scopas
Name: Ornate Leopard Blenny
Order: Blenniiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Exallodontus ligulatus
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Name: Ornate Sand Diver (Synodus)
Order: Aulopiformes
Habitat: Tropical Marine (sandy bottoms)
Scientific name: Synodus ornatus
Name: Ornate Sandperch
Order: Perciformes
Habitat: Temperate Marine (sandy bottoms)
Scientific name: Parapercis allporti
Name: Ornate Sleeper Ray
Order: Torpediniformes
Habitat: Tropical Marine (benthic)
Scientific name: Torpedo panthera
Name: Ornate Soldierfish
Order: Beryciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Myripristis murdjan
Name: Ornate Sole
Order: Pleuronectiformes
Habitat: Tropical Marine (benthic)
Scientific name: Solea aquispeculi
Name: Ornate Threadfin Bream
Order: Perciformes
Habitat: Tropical Marine (benthic)
Scientific name: Nemipterus ornatus
Name: Ornate Waspfish
Order: Scorpaeniformes
Habitat: Tropical Marine (benthic)
Scientific name: Liocranium praepositum
Name: Ornate Worm Goby
Order: Gobiiformes
Habitat: Tropical Marine (burrows)
Scientific name: Pholidichthys leucotaenia
Name: Ornate Wrasse
Order: Perciformes
Habitat: Mediterranean Sea (rocky reefs)
Scientific name: Thalassoma pavo
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Name: Ornate Wrasse (Thalassoma)
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Thalassoma hardwicke
Name: Orthodox Shark
Order: Carcharhiniformes
Habitat: Pelagic (tropical and subtropical)
Scientific name: Carcharhinus longimanus
Name: Osaka Flasher Bream
Order: Perciformes
Habitat: Indo-Pacific (estuaries and coastal waters)
Scientific name: Argyrops spinifer
Name: Oscar
Order: Cichliformes
Habitat: Freshwater (South America)
Scientific name: Astronotus ocellatus
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Name: Oscar (red)
Order: Cichliformes
Habitat: Freshwater (South America)
Scientific name: Astronotus rubroocellatus
Name: Oscillating Pipefish
Order: Syngnathiformes
Habitat: Freshwater (Indo-Pacific)
Scientific name: Microphis smithi
Name: Osteoglossid
Order: Osteoglossiformes
Habitat: Freshwater (South America)
Scientific name: Osteoglossum bicirrhosum
Name: Ostracion Cube
Order: Tetraodontiformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Ostracion cubicus
Name: Outer Reef Damselfish
Order: Perciformes
Habitat: Tropical Marine (coral reefs)
Scientific name: Dascyllus marginatus
Name: Ovate Croaker
Order: Perciformes
Habitat: Tropical Marine (coastal)
Scientific name: Larimichthys pamoides
Name: Overcast Sea Perch
Order: Perciformes
Habitat: Temperate Pacific (rocky reefs)
Scientific name: Stereolepis gigas
Name: Oviparous Brotula
Order: Ophidiiformes
Habitat: Deep Sea (benthic)
Scientific name: Brotula multibarbata
Name: Owlfish
Order: Perciformes
Habitat: Deep Sea (pelagic)
Scientific name: Bathophilus flemingi
Name: Oxford Netted Dogfish
Order: Squaliformes
Habitat: Deep Sea (Atlantic)
Scientific name: Apristurus maderensis
| Name | Order | Habitat | Scientific name |
|---|---|---|---|
| Oarfish | Lampriformes | Deep Pelagic | Regalecus glesne |
| Oarfish (giant) | Lampriformes | Deep Pelagic | Regalecus russelii |
| Oblique Cardinalfish | Perciformes | Tropical Marine (coral reefs) | Apogon obliquus |
| Oblique Sweetlips | Perciformes | Tropical Marine (coral reefs) | Plectorhinchus macrolepis |
| Oblique-banded Pipefish | Syngnathiformes | Tropical Marine (coral reefs) | Corythoichthys ocellatus |
| Oblique-banded Seabream | Perciformes | Mediterranean Sea (coastal) | Oblada melanura |
| Oblique-banded Snapper | Perciformes | Tropical Marine (coral reefs) | Lutjanus vitta |
| Oblong Pipefish | Syngnathiformes | Tropical Marine (coral reefs) | Halicampus macrorhynchus |
| Oblong Silver Biddy | Perciformes | Tropical Marine (coastal) | Gerres oblongus |
| Oblong Snapper | Perciformes | Tropical Marine (coral reefs) | Lutjanus oblongus |
| Oblong Sole | Pleuronectiformes | Tropical Marine (benthic) | Solea oblonga |
| Oblong Sunfish | Perciformes | Freshwater (North America) | Enneacanthus elongatus |
| Ocean Pout | Perciformes | Temperate Atlantic Ocean (benthic) | Macrozoarces americanus |
| Ocean Sunfish | Tetraodontiformes | Pelagic (open ocean) | Mola mola |
| Ocean Triggerfish | Tetraodontiformes | Pelagic (tropical and subtropical) | Canthidermis maculata |
| Oceanic Bass | Perciformes | Deep Sea (Comoros Islands) | Latimeria chalumnae |
| Oceanic Basslet | Perciformes | Deep Sea (benthic) | Hemanthias vivanus |
| Oceanic Flyingfish | Beloniformes | Pelagic (tropical and subtropical) | Exocoetus volitans |
| Oceanic Garfish | Beloniformes | Pelagic (tropical and subtropical) | Tylosurus acus |
| Oceanic Sargo | Perciformes | Eastern Pacific (coastal) | Anisotremus interruptus |
| Oceanic Sunfish (Mola) | Tetraodontiformes | Pelagic (open ocean) | Mola mola |
| Oceanic Tripod Fish | Aulopiformes | Deep Sea (benthic) | Bathymicrops regis |
| Oceanic Whitetip Shark | Carcharhiniformes | Pelagic (tropical and subtropical) | Carcharhinus longimanus |
| Ocellaris Clownfish | Perciformes | Tropical Marine (coral reefs) | Amphiprion ocellaris |
| Ocellate Moray (Gymnothorax ocellatus) | Anguilliformes | Tropical Marine (coral reefs) | Gymnothorax ocellatus |
| Ocellate Snapper | Perciformes | Western Atlantic (tropical) | Lutjanus campechanus |
| Ocellated Barbfish | Scorpaeniformes | Tropical Marine (coral reefs) | Scorpaena histrio |
| Ocellated Barred Goby | Gobiiformes | Tropical Marine (coral reefs) | Priolepis nocturna |
| Ocellated Dragonet | Perciformes | Tropical Marine (coral reefs) | Synchiropus ocellatus |
| Ocellated Dragonfish | Stomiiformes | Deep Sea (pelagic) | Malacosteus niger |
| Ocellated Flathead | Scorpaeniformes | Tropical Marine (benthic) | Platycephalus ocellatus |
| Ocellated Flounder | Pleuronectiformes | Western Atlantic (benthic) | Ancylopsetta quadrocellata |
| Ocellated Frogfish | Lophiiformes | Western Atlantic (tropical) | Antennarius ocellatus |
| Ocellated Moray | Anguilliformes | Tropical Marine (coral reefs) | Gymnothorax ocellatus |
| Ocellated Pipefish | Syngnathiformes | Tropical Marine (coral reefs) | Corythoichthys ocellatus |
| Ocellated Razorfish | Perciformes | Tropical Marine (sandy bottoms) | Xyrichtys novacula |
| Ocellated Sand Diver | Perciformes | Western Atlantic (sandy bottoms) | Synodus ocellaris |
| Ocellated Scorpionfish | Scorpaeniformes | Tropical Marine (coral reefs) | Scorpaenopsis neglecta |
| Ocellated Skate | Rajiformes | Temperate Atlantic (benthic) | Raja ocellata |
| Ocellated Snake Eel | Anguilliformes | Tropical Marine (sandy bottoms) | Ophichthus ocellatus |
| Ocellated Stargazer | Perciformes | Tropical Marine (benthic) | Gnathagnus cribratus |
| Ocellated Toby | Tetraodontiformes | Tropical Marine (coral reefs) | Canthigaster ocellicincta |
| Ocellated Velvetfish | Scorpaeniformes | Indo-Pacific (benthic) | Anema ocellata |
| Ocellated Wrasse | Perciformes | Mediterranean Sea (rocky reefs) | Symphodus ocellatus |
| Octopusfish | Scorpaeniformes | Tropical Marine (coral reefs) | Scorpaenopsis venosa |
| Odd Gurnard | Scorpaeniformes | Deep Sea (benthic) | Satyrichthys rieffeli |
| Ogilby's Wrasse | Perciformes | Mediterranean Sea (rocky reefs) | Symphodus rostratus |
| Oilfish | Perciformes | Deep Pelagic (tropical and temperate waters) | Ruvettus pretiosus |
| Okhotsk Atka Mackerel | Scorpaeniformes | Temperate North Pacific (benthic) | Pleurogrammus azonus |
| Old English Sheepdog Wrasse | Perciformes | Tropical Marine (coral reefs) | Halichoeres hortulanus |
| Old Wife | Perciformes | Temperate Australian Marine (coastal reefs) | Enoplosus armatus |
| Old Wife Cod | Gadiformes | Tropical Marine (deep water) | Bregmaceros macclellandi |
| Olive Blenny | Blenniiformes | Tropical Marine (coral reefs) | Cirripectes castaneus |
| Olive Blenny (Hypsoblennius) | Blenniiformes | Eastern Pacific (rocky shores) | Hypsoblennius sordidus |
| Olive Bonito | Scombriformes | Tropical Atlantic (pelagic) | Orcynopsis unicolor |
| Olive Flounder | Pleuronectiformes | Temperate Pacific Ocean (benthic) | Paralichthys olivaceus |
| Olive Rockfish | Perciformes | Temperate Pacific (rocky reefs) | Sebastes serranoides |
| Olive Scorpionfish | Scorpaeniformes | Tropical Marine (coral reefs) | Scorpaenopsis venosa |
| Omani Sole | Pleuronectiformes | Tropical Marine (benthic) | Solea omanensis |
| One Spot Cardinalfish | Perciformes | Tropical Marine (coral reefs) | Apogon unicolor |
| One-spot Flasher Wrasse | Perciformes | Tropical Marine (coral reefs) | Paracheilinus octotaenia |
| Onefin Catfish | Siluriformes | Freshwater (Africa) | Synodontis eupterus |
| Onefin Flashlight Fish | Myctophiformes | Tropical Marine (deep reef) | Photoblepharon palpebratum |
| Onefin Ghostfish | Aulopiformes | Pelagic (deep sea) | Anotopterus vorax |
| Onion Brotula | Ophidiiformes | Deep Sea (benthic) | Brotula barbata |
| Onionfish | Perciformes | Temperate Atlantic (benthic) | Ogcocephalus radiatus |
| Opah | Lampriformes | Deep Pelagic (tropical and temperate waters) | Lampris guttatus |
| Open Ocean Dolphin Fish | Perciformes | Pelagic (tropical and subtropical) | Coryphaena hippurus |
| Opossum Pipefish | Syngnathiformes | Brackish/Freshwater (Indo-Pacific) | Microphis brachyurus |
| Opposite-sex Pipefish | Syngnathiformes | Tropical Marine (coral reefs) | Corythoichthys paxtoni |
| Orange Anemonefish | Perciformes | Tropical Marine (coral reefs) | Amphiprion percula |
| Orange Basslet | Perciformes | Tropical Marine (coral reefs) | Liopropoma carmabi |
| Orange Blotch Hap | Cichliformes | Freshwater (Lake Malawi) | Maylandia callainos |
| Orange Blotched Triggerfish | Tetraodontiformes | Tropical Marine (coral reefs) | Rhinecanthus verrucosus |
| Orange Butterflyfish | Perciformes | Tropical Marine (coral reefs) | Chaetodon kleinii |
| Orange Damsel | Perciformes | Tropical Marine (coral reefs) | Abudefduf vaigiensis |
| Orange Goby | Gobiiformes | Tropical Marine (coral reefs) | Gobiodon citrinus |
| Orange Razorfish | Perciformes | Tropical Marine (sandy bottoms) | Iniistius uwii |
| Orange Roughy | Beryciformes | Deep Sea (benthic) | Hoplostethus atlanticus |
| Orange Roughy (juvenile) | Beryciformes | Deep Sea (pelagic to benthic) | Hoplostethus atlanticus |
| Orange Skunk Clownfish | Perciformes | Tropical Marine (coral reefs) | Amphiprion akallopisos |
| Orange Snapper | Perciformes | Tropical Marine (coral reefs) | Lutjanus fulvus |
| Orange Spotted Blenny | Blenniiformes | Tropical Marine (rocky shores) | Istiblennius spilotus |
| Orange Spotted Moray | Anguilliformes | Tropical Marine (coral reefs) | Gymnothorax meleagris |
| Orange Unicornfish | Perciformes | Tropical Marine (coral reefs) | Naso maculatus |
| Orange-banded Coralfish | Perciformes | Tropical Marine (coral reefs) | Chaetodon ornatissimus |
| Orange-barred Emperor | Perciformes | Tropical Marine (coral reefs) | Lethrinus kallopterus |
| Orange-breasted Sunfish | Perciformes | Freshwater (North America) | Lepomis auritus |
| Orange-dotted Tuskfish | Perciformes | Tropical Marine (coral reefs) | Choerodon anchorago |
| Orange-fin Squirrelfish | Beryciformes | Tropical Marine (coral reefs) | Sargocentron cornutum |
| Orange-lined Cardinalfish | Perciformes | Tropical Marine (coral reefs) | Apogon compressus |
| Orange-lined Fairy Wrasse | Perciformes | Tropical Marine (coral reefs) | Cirrhilabrus lineatus |
| Orange-lined Squirrelfish | Beryciformes | Tropical Marine (coral reefs) | Sargocentron rubrum |
| Orange-lined Triggerfish | Tetraodontiformes | Tropical Marine (coral reefs) | Balistapus undulatus |
| Orange-spotted Blenny | Blenniiformes | Tropical Marine (coral reefs) | Salarias fasciatus |
| Orange-spotted Catshark | Carcharhiniformes | Tropical Marine (benthic) | Chiloscyllium plagiosum |
| Orange-spotted Filefish | Tetraodontiformes | Tropical Marine (coral reefs) | Oxymonacanthus longirostris |
| Orange-spotted Grouper | Perciformes | Tropical Marine (coral reefs) | Epinephelus coioides |
| Orange-spotted Isoscelesfish | Perciformes | Temperate Marine (coastal) | Upeneichthys lineatus |
| Orange-spotted Spinefoot | Perciformes | Tropical Marine (coral reefs) | Siganus guttatus |
| Orange-spotted Trevally | Carangiformes | Tropical Marine (coastal) | Carangoides fulvoguttatus |
| Orange-spotted Wrasse | Perciformes | Tropical Marine (coral reefs) | Bodianus opercularis |
| Orange-striped Cardinalfish | Perciformes | Tropical Marine (coral reefs) | Apogon cyanosoma |
| Orange-striped Triggerfish | Tetraodontiformes | Tropical Marine (coral reefs) | Sufflamen chrysopterum |
| Orange-tipped Cardinalfish | Perciformes | Tropical Marine (coral reefs) | Apogon nigripes |
| Orangeback Anglerfish | Lophiiformes | Temperate Atlantic (benthic) | Lophius americanus |
| Orangeback Bass | Perciformes | Atlantic Ocean (benthic) | Serranus annularis |
| Orangebanded Coralfish | Perciformes | Tropical Marine (coral reefs) | Chaetodon ornatissimus |
| Orangechin Triggerfish | Tetraodontiformes | Tropical Marine (coral reefs) | Xanthichthys caeruleolineatus |
| Orangefin Butterflyfish | Perciformes | Tropical Marine (coral reefs) | Chaetodon xanthurus |
| Orangefin Piranha | Characiformes | Freshwater (South America) | Serrasalmus rhombeus |
| Orangefin Surgeonfish | Perciformes | Tropical Marine (coral reefs) | Acanthurus auranticavus |
| Orangehead Filefish | Tetraodontiformes | Tropical Marine (coastal) | Monacanthus hispidus |
| Orangehead Hawkfish | Perciformes | Tropical Marine (coral reefs) | Paracirrhites arcatus |
| Orangespine Squirrelfish | Beryciformes | Tropical Marine (coral reefs) | Sargocentron spiniferum |
| Orangespine Unicornfish | Perciformes | Tropical Marine (coral reefs) | Naso lituratus |
| Orangespot Surgeonfish | Perciformes | Tropical Marine (coral reefs) | Acanthurus olivaceus |
| Orangespot Wrasse | Perciformes | Tropical Marine (coral reefs) | Halichoeres melanurus |
| Orangestriped Goatfish | Perciformes | Tropical Marine (sandy bottoms) | Upeneus taeniopterus |
| Orangethroat Darter | Perciformes | Freshwater (North America) | Etheostoma spectabile |
| Orcaella Wrasses | Perciformes | Tropical Marine (coral reefs) | Cheilinus orans |
| Orchard Goby | Gobiiformes | Freshwater (North America) | Ctenogobius sp. |
| Orconaut | Perciformes | Tropical Marine (moray eel) | Gymnothorax ocellatus |
| Oregon Chub | Cypriniformes | Freshwater (North America) | Oregonichthys crameri |
| Oregon Spotted Frogfish | Lophiiformes | Eastern Pacific (benthic) | Antennarius pardalis |
| Oriental Flying Gurnard | Scorpaeniformes | Tropical Marine (sandy bottoms) | Dactyloptena orientalis |
| Oriental Sweetlips | Perciformes | Tropical Marine (coral reefs) | Plectorhinchus vittatus |
| Ornate Anglerfish | Lophiiformes | Tropical Marine (coral reefs) | Antennarius commerson |
| Ornate Boxfish | Tetraodontiformes | Tropical Marine (coral reefs) | Ostracanthus ornatissimus |
| Ornate Butterflyfish | Perciformes | Tropical Marine (coral reefs) | Chaetodon reticulatus |
| Ornate Coralfish | Perciformes | Tropical Marine (coral reefs) | Coradion ornatissimus |
| Ornate Flounder | Pleuronectiformes | Temperate Marine (benthic) | Arnoglossus armstrongi |
| Ornate Frogfish | Lophiiformes | Tropical Marine (coral reefs) | Antennarius pictus |
| Ornate Ghost Pipefish | Syngnathiformes | Tropical Marine (coral reefs) | Solenostomus paradoxus |
| Ornate Leatherjacket | Tetraodontiformes | Tropical Marine (coral reefs) | Amanses scopas |
| Ornate Leopard Blenny | Blenniiformes | Tropical Marine (coral reefs) | Exallodontus ligulatus |
| Ornate Sand Diver (Synodus) | Aulopiformes | Tropical Marine (sandy bottoms) | Synodus ornatus |
| Ornate Sandperch | Perciformes | Temperate Marine (sandy bottoms) | Parapercis allporti |
| Ornate Sleeper Ray | Torpediniformes | Tropical Marine (benthic) | Torpedo panthera |
| Ornate Soldierfish | Beryciformes | Tropical Marine (coral reefs) | Myripristis murdjan |
| Ornate Sole | Pleuronectiformes | Tropical Marine (benthic) | Solea aquispeculi |
| Ornate Threadfin Bream | Perciformes | Tropical Marine (benthic) | Nemipterus ornatus |
| Ornate Waspfish | Scorpaeniformes | Tropical Marine (benthic) | Liocranium praepositum |
| Ornate Worm Goby | Gobiiformes | Tropical Marine (burrows) | Pholidichthys leucotaenia |
| Ornate Wrasse | Perciformes | Mediterranean Sea (rocky reefs) | Thalassoma pavo |
| Ornate Wrasse (Thalassoma) | Perciformes | Tropical Marine (coral reefs) | Thalassoma hardwicke |
| Orthodox Shark | Carcharhiniformes | Pelagic (tropical and subtropical) | Carcharhinus longimanus |
| Osaka Flasher Bream | Perciformes | Indo-Pacific (estuaries and coastal waters) | Argyrops spinifer |
| Oscar | Cichliformes | Freshwater (South America) | Astronotus ocellatus |
| Oscar (red) | Cichliformes | Freshwater (South America) | Astronotus rubroocellatus |
| Oscillating Pipefish | Syngnathiformes | Freshwater (Indo-Pacific) | Microphis smithi |
| Osteoglossid | Osteoglossiformes | Freshwater (South America) | Osteoglossum bicirrhosum |
| Ostracion Cube | Tetraodontiformes | Tropical Marine (coral reefs) | Ostracion cubicus |
| Outer Reef Damselfish | Perciformes | Tropical Marine (coral reefs) | Dascyllus marginatus |
| Ovate Croaker | Perciformes | Tropical Marine (coastal) | Larimichthys pamoides |
| Overcast Sea Perch | Perciformes | Temperate Pacific (rocky reefs) | Stereolepis gigas |
| Oviparous Brotula | Ophidiiformes | Deep Sea (benthic) | Brotula multibarbata |
| Owlfish | Perciformes | Deep Sea (pelagic) | Bathophilus flemingi |
| Oxford Netted Dogfish | Squaliformes | Deep Sea (Atlantic) | Apristurus maderensis |