All aquarium species: O
All species whose common name starts with O, in alphabetical order. Each card links to its care guide.
84 species and 23 varieties
Oaxaca vieja
Vieja zonata
Freshwater9.8 in (25 cm) · 132 gal (500 L)75–84°F (24–29°C)
OB peacock cichlid
Aulonocara hybrid
Freshwater5.9 in (15 cm) · 63 gal (240 L)75–82°F (24–28°C)2 varietiesObscura betta
Betta obscura
Freshwater2.7 in (6.9 cm) · 20 gal (75 L)72–81°F (22–27°C)
Ocellaris clownfish
Amphiprion ocellaris
Saltwater3.1 in (8 cm) · 20 gal (75 L)75–82°F (24–28°C)17 varieties
Ocellate river stingray
Potamotrygon motoro
Freshwater19.7 in (50 cm) · 264 gal (1,000 L)75–82°F (24–28°C)
Ocellated kribensis
Pelvicachromis subocellatus
Freshwater3.9 in (10 cm) · 21 gal (80 L)75–81°F (24–27°C)
Ocellated puffer
Leiodon cutcutia
Freshwater5.9 in (15 cm) · 29 gal (110 L)75–82°F (24–28°C)
Ocellated snakehead
Channa pleurophthalma
Freshwater15.7 in (40 cm) · 70 gal (265 L)75–82°F (24–28°C)
Ocellated squeaker
Synodontis ocellifer
Freshwater7.9 in (20 cm) · 53 gal (200 L)73–81°F (23–27°C)
Octospawn coral
Fimbriaphyllia yaeyamaensis
Saltwater7.9 in (20 cm) · 20 gal (75 L)75–81°F (24–27°C)
Odessa barb
Pethia padamya
Freshwater1.8 in (4.5 cm) · 20 gal (75 L)61–77°F (16–25°C)
Odo cichlid
Nandopsis haitiensis
Freshwater10.2 in (26 cm) · 132 gal (500 L)75–84°F (24–29°C)
Ogilbie's osteobrama
Rohtee ogilbii
Freshwater7.9 in (20 cm) · 66 gal (250 L)68–81°F (20–27°C)
Ogilby's rainbowfish
Melanotaenia ogilbyi
Freshwater3.1 in (8 cm) · 29 gal (110 L)75–84°F (24–29°C)
Ogilvie's lizard loach
Homaloptera ogilviei
Freshwater2.4 in (6 cm) · 20 gal (75 L)70–79°F (21–26°C)
Ogowe killifish
Aphyosemion ogoense
Freshwater2 in (5 cm) · 11 gal (40 L)64–73°F (18–23°C)
Oiapoque cory
Hoplisoma oiapoquense
Freshwater2.2 in (5.5 cm) · 20 gal (75 L)73–79°F (23–26°C)
Oil catfish
Duringlanis perugiae
Freshwater2.4 in (6 cm) · 15 gal (55 L)75–82°F (24–28°C)
Okinawa cleaner shrimp
Neocaridina denticulata
Freshwater1.2 in (3 cm) · 5 gal (20 L)64–79°F (18–26°C)
Olive nerite
Vittina usnea
FreshwaterBrackish0.8 in (2 cm) · 5 gal (20 L)72–82°F (22–28°C)Omega betta
Betta omega
Freshwater3.2 in (8.1 cm) · 24 gal (90 L)73–81°F (23–27°C)
Ommation whiptail
Rhadinoloricaria ommation
Freshwater5.7 in (14.5 cm) · 40 gal (150 L)73–82°F (23–28°C)
Ompok catfish
Ompok pabda
Freshwater11.8 in (30 cm) · 106 gal (400 L)73–81°F (23–27°C)
One-lined pencilfish
Nannostomus unifasciatus
Freshwater1.6 in (4 cm) · 17 gal (65 L)73–82°F (23–28°C)
One-spot betta
Betta unimaculata
Freshwater4.5 in (11.5 cm) · 29 gal (110 L)70–79°F (21–26°C)
One-spot foxface
Siganus unimaculatus
Saltwater7.9 in (20 cm) · 70 gal (265 L)75–81°F (24–27°C)
One-spot synodontis
Synodontis notatus
Freshwater9.8 in (25 cm) · 53 gal (200 L)72–81°F (22–27°C)
One-stripe spiny eel
Macrognathus aral
Freshwater23.6 in (60 cm) · 119 gal (450 L)73–82°F (23–28°C)
Onespot barb
Puntius terio
Freshwater3.1 in (8 cm) · 20 gal (75 L)68–79°F (20–26°C)
Opae ula
Halocaridina rubra
Brackish0.6 in (1.5 cm) · 1 gal (4 L)68–82°F (20–28°C)
Opal licorice gourami
Parosphromenus opallios
Freshwater1.2 in (3 cm) · 5 gal (20 L)72–81°F (22–27°C)
Opal spot pleco
Scobinancistrus raonii
Freshwater6.3 in (16 cm) · 79 gal (300 L)81–88°F (27–31°C)
Open brain coral
Trachyphyllia geoffroyi
Saltwater5.9 in (15 cm) · 11 gal (40 L)75–81°F (24–27°C)
Opossum pipefish
Microphis brachyurus
FreshwaterBrackish8.7 in (22 cm) · 32 gal (120 L)75–82°F (24–28°C)
Orange chromide
Etroplus maculatus
FreshwaterBrackish3.9 in (10 cm) · 55 gal (210 L)68–82°F (20–28°C)
Orange Congo tetra
Phenacogrammus aurantiacus
Freshwater3.9 in (10 cm) · 42 gal (160 L)73–81°F (23–27°C)
Orange dwarf crayfish
Cambarellus patzcuarensis
Freshwater2 in (5 cm) · 10 gal (38 L)64–77°F (18–25°C)
Orange fin goby
Stiphodon maculidorsalis
Freshwater2.2 in (5.5 cm) · 14 gal (54 L)73–81°F (23–27°C)
Orange hatchet danio
Laubuka dadiburjori
Freshwater1.2 in (3 cm) · 13 gal (50 L)68–75°F (20–24°C)
Orange marble bee catfish
Akysis longifilis
Freshwater2.4 in (6 cm) · 14 gal (54 L)72–79°F (22–26°C)
Orange seam pleco
Hemiancistrus guahiborum
Freshwater5.5 in (14 cm) · 66 gal (250 L)77–84°F (25–29°C)
Orange skunk clownfish
Amphiprion sandaracinos
Saltwater5.5 in (14 cm) · 30 gal (115 L)75–82°F (24–28°C)
Orange vampire crab
Geosesarma tiomanicum
Freshwater2 in (5 cm) · 11 gal (40 L)72–82°F (22–28°C)
Orange-finned danio
Danio kyathit
Freshwater2 in (5 cm) · 20 gal (75 L)68–79°F (20–26°C)
Orange-spot prawn goby
Amblyeleotris guttata
Saltwater4.3 in (11 cm) · 30 gal (114 L)72–79°F (22–26°C)
Orange-spotted snakehead
Channa aurantimaculata
Freshwater15.7 in (40 cm) · 119 gal (450 L)59–77°F (15–25°C)
Orangeshoulder tang
Acanthurus olivaceus
Saltwater13.8 in (35 cm) · 180 gal (680 L)75–82°F (24–28°C)
Orangethroat darter
Etheostoma spectabile
Freshwater2.8 in (7 cm) · 25 gal (95 L)59–68°F (15–20°C)
Orbiculate batfish
Platax orbicularis
Saltwater19.7 in (50 cm) · 185 gal (700 L)75–81°F (24–27°C)
Orbiculate cardinalfish
Sphaeramia orbicularis
Saltwater3.9 in (10 cm) · 30 gal (115 L)75–82°F (24–28°C)
Orces's cory
Corydoras orcesi
Freshwater2.4 in (6 cm) · 20 gal (75 L)73–81°F (23–27°C)
Orchid dottyback
Pseudochromis fridmani
Saltwater2.8 in (7 cm) · 29 gal (110 L)72–79°F (22–26°C)
Organ pipe coral
Tubipora musica
Saltwater9.8 in (25 cm) · 11 gal (40 L)75–81°F (24–27°C)
Orientalis squeaker
Synodontis orientalis
Freshwater4.3 in (11 cm) · 42 gal (160 L)73–81°F (23–27°C)
Orinoco angel pleco (L201)
Hypancistrus sp. L201
Freshwater5.9 in (15 cm) · 30 gal (115 L)79–86°F (26–30°C)
Orinoco cupid cichlid
Biotodoma wavrini
Freshwater4.7 in (12 cm) · 66 gal (250 L)77–84°F (25–29°C)
Orinoco dolphin catfish
Ageneiosus magoi
Freshwater7.1 in (18 cm) · 106 gal (400 L)73–82°F (23–28°C)
Orinoco dwarf pleco
Peckoltia lineola
Freshwater4.3 in (11 cm) · 29 gal (110 L)77–84°F (25–29°C)
Orinoco flagtail prochilodus
Semaprochilodus laticeps
Freshwater17.3 in (44 cm) · 264 gal (1,000 L)73–82°F (23–28°C)
Orinoco peacock bass
Cichla orinocensis
Freshwater24.4 in (62 cm) · 528 gal (2,000 L)77–86°F (25–30°C)
Orinoco peckoltia
Peckoltia lujani
Freshwater3.5 in (9 cm) · 29 gal (110 L)77–84°F (25–29°C)
Orinoco polka-dot pleco
Hypancistrus contradens
Freshwater4.7 in (12 cm) · 42 gal (160 L)79–86°F (26–30°C)
Orinoco spotted raphael
Agamyxis albomaculatus
Freshwater5.9 in (15 cm) · 40 gal (150 L)73–82°F (23–28°C)
Orinoco talking catfish
Orinocodoras eigenmanni
Freshwater7.9 in (20 cm) · 70 gal (265 L)73–82°F (23–28°C)
Ornate bichir
Polypterus ornatipinnis
Freshwater21.7 in (55 cm) · 172 gal (650 L)77–82°F (25–28°C)
Ornate bushfish
Microctenopoma ansorgii
Freshwater3.1 in (8 cm) · 20 gal (75 L)73–81°F (23–27°C)
Ornate cory
Brochis ornata
Freshwater2.8 in (7 cm) · 24 gal (90 L)72–79°F (22–26°C)
Ornate garra
Garra ornata
Freshwater4.3 in (11 cm) · 29 gal (110 L)72–81°F (22–27°C)
Ornate hap
Protomelas ornatus
Freshwater7.2 in (18.2 cm) · 106 gal (400 L)75–82°F (24–28°C)
Ornate paradisefish
Malpulutta kretseri
Freshwater2 in (5 cm) · 12 gal (45 L)72–82°F (22–28°C)
Ornate pimelodus
Pimelodus ornatus
Freshwater12.2 in (31 cm) · 65 gal (245 L)75–82°F (24–28°C)
Ornate rainbowfish
Rhadinocentrus ornatus
Freshwater2.4 in (6 cm) · 20 gal (75 L)64–82°F (18–28°C)
Ornate shell dweller
Lamprologus ornatipinnis
Freshwater2.4 in (6 cm) · 16 gal (60 L)75–81°F (24–27°C)
Ornate stone loach
Nemacheilus ornatus
Freshwater2 in (5 cm) · 20 gal (75 L)72–79°F (22–26°C)
Ornate tetra
Hyphessobrycon bentosi
Freshwater1.8 in (4.5 cm) · 20 gal (75 L)72–82°F (22–28°C)
Ornate-tail Borneo sucker
Gastromyzon ornaticauda
Freshwater3.3 in (8.4 cm) · 24 gal (90 L)68–77°F (20–25°C)
Ornate-tail licorice gourami
Parosphromenus ornaticauda
Freshwater0.9 in (2.4 cm) · 5 gal (20 L)72–81°F (22–27°C)
Ortega's cory
Hoplisoma ortegai
Freshwater2 in (5 cm) · 16 gal (60 L)73–81°F (23–27°C)
Ortega's dwarf cichlid
Apistogramma ortegai
Freshwater2.6 in (6.5 cm) · 16 gal (60 L)75–82°F (24–28°C)
Oscar
Astronotus ocellatus
Freshwater13.8 in (35 cm) · 95 gal (360 L)68–82°F (20–28°C)4 varieties
Ourastigma cory
Corydoras ourastigma
Freshwater2.6 in (6.5 cm) · 20 gal (75 L)75–82°F (24–28°C)
Owroewefi guianacara
Guianacara owroewefi
Freshwater5.1 in (13 cm) · 66 gal (250 L)77–84°F (25–29°C)
Oxypora chalice coral
Oxypora lacera
Saltwater9.8 in (25 cm) · 26 gal (100 L)75–81°F (24–27°C)
Oxyrhynchus hap
Hemitilapia oxyrhynchus
Freshwater7.9 in (20 cm) · 119 gal (450 L)75–81°F (24–27°C)
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