Bottom-dwelling aquarium fish: O

All bottom dwellers whose common name starts with O, in alphabetical order. Each card links to its care guide.

39 species and 2 varieties

• 

  Oaxaca vieja

  Vieja zonata

  Freshwater
  9.8 in (25 cm) · 132 gal (500 L)75–84°F (24–29°C)

• 

  OB peacock cichlid

  Aulonocara hybrid

  Freshwater
  5.9 in (15 cm) · 63 gal (240 L)75–82°F (24–28°C)2 varieties

• 

  Ocellate river stingray

  Potamotrygon motoro

  Freshwater
  19.7 in (50 cm) · 264 gal (1,000 L)75–82°F (24–28°C)

• 

  Ocellated kribensis

  Pelvicachromis subocellatus

  Freshwater
  3.9 in (10 cm) · 21 gal (80 L)75–81°F (24–27°C)

• 

  Ocellated squeaker

  Synodontis ocellifer

  Freshwater
  7.9 in (20 cm) · 53 gal (200 L)73–81°F (23–27°C)

• 

  Odo cichlid

  Nandopsis haitiensis

  Freshwater
  10.2 in (26 cm) · 132 gal (500 L)75–84°F (24–29°C)

• 

  Ogilvie's lizard loach

  Homaloptera ogilviei

  Freshwater
  2.4 in (6 cm) · 20 gal (75 L)70–79°F (21–26°C)

• 

  Oiapoque cory

  Hoplisoma oiapoquense

  Freshwater
  2.2 in (5.5 cm) · 20 gal (75 L)73–79°F (23–26°C)

• 

  Oil catfish

  Duringlanis perugiae

  Freshwater
  2.4 in (6 cm) · 15 gal (55 L)75–82°F (24–28°C)

• 

  Ommation whiptail

  Rhadinoloricaria ommation

  Freshwater
  5.7 in (14.5 cm) · 40 gal (150 L)73–82°F (23–28°C)

• 

  One-spot synodontis

  Synodontis notatus

  Freshwater
  9.8 in (25 cm) · 53 gal (200 L)72–81°F (22–27°C)

• 

  One-stripe spiny eel

  Macrognathus aral

  Freshwater
  23.6 in (60 cm) · 119 gal (450 L)73–82°F (23–28°C)

• 

  Opal spot pleco

  Scobinancistrus raonii

  Freshwater
  6.3 in (16 cm) · 79 gal (300 L)81–88°F (27–31°C)

• 

  Opossum pipefish

  Microphis brachyurus

  Freshwater·Brackish
  8.7 in (22 cm) · 32 gal (120 L)75–82°F (24–28°C)

• 

  Orange fin goby

  Stiphodon maculidorsalis

  Freshwater
  2.2 in (5.5 cm) · 14 gal (54 L)73–81°F (23–27°C)

• 

  Orange marble bee catfish

  Akysis longifilis

  Freshwater
  2.4 in (6 cm) · 14 gal (54 L)72–79°F (22–26°C)

• 

  Orange seam pleco

  Hemiancistrus guahiborum

  Freshwater
  5.5 in (14 cm) · 66 gal (250 L)77–84°F (25–29°C)

• 

  Orangethroat darter

  Etheostoma spectabile

  Freshwater
  2.8 in (7 cm) · 25 gal (95 L)59–68°F (15–20°C)

• 

  Orces's cory

  Corydoras orcesi

  Freshwater
  2.4 in (6 cm) · 20 gal (75 L)73–81°F (23–27°C)

• 

  Orientalis squeaker

  Synodontis orientalis

  Freshwater
  4.3 in (11 cm) · 42 gal (160 L)73–81°F (23–27°C)

• 

  Orinoco angel pleco (L201)

  Hypancistrus sp. L201

  Freshwater
  5.9 in (15 cm) · 30 gal (115 L)79–86°F (26–30°C)

• 

  Orinoco cupid cichlid

  Biotodoma wavrini

  Freshwater
  4.7 in (12 cm) · 66 gal (250 L)77–84°F (25–29°C)

• 

  Orinoco dwarf pleco

  Peckoltia lineola

  Freshwater
  4.3 in (11 cm) · 29 gal (110 L)77–84°F (25–29°C)

• 

  Orinoco peckoltia

  Peckoltia lujani

  Freshwater
  3.5 in (9 cm) · 29 gal (110 L)77–84°F (25–29°C)

• 

  Orinoco polka-dot pleco

  Hypancistrus contradens

  Freshwater
  4.7 in (12 cm) · 42 gal (160 L)79–86°F (26–30°C)

• 

  Orinoco spotted raphael

  Agamyxis albomaculatus

  Freshwater
  5.9 in (15 cm) · 40 gal (150 L)73–82°F (23–28°C)

• 

  Orinoco talking catfish

  Orinocodoras eigenmanni

  Freshwater
  7.9 in (20 cm) · 70 gal (265 L)73–82°F (23–28°C)

• 

  Ornate bichir

  Polypterus ornatipinnis

  Freshwater
  21.7 in (55 cm) · 172 gal (650 L)77–82°F (25–28°C)

• 

  Ornate cory

  Brochis ornata

  Freshwater
  2.8 in (7 cm) · 24 gal (90 L)72–79°F (22–26°C)

• 

  Ornate garra

  Garra ornata

  Freshwater
  4.3 in (11 cm) · 29 gal (110 L)72–81°F (22–27°C)

• 

  Ornate pimelodus

  Pimelodus ornatus

  Freshwater
  12.2 in (31 cm) · 65 gal (245 L)75–82°F (24–28°C)

• 

  Ornate shell dweller

  Lamprologus ornatipinnis

  Freshwater
  2.4 in (6 cm) · 16 gal (60 L)75–81°F (24–27°C)

• 

  Ornate stone loach

  Nemacheilus ornatus

  Freshwater
  2 in (5 cm) · 20 gal (75 L)72–79°F (22–26°C)

• 

  Ornate-tail Borneo sucker

  Gastromyzon ornaticauda

  Freshwater
  3.3 in (8.4 cm) · 24 gal (90 L)68–77°F (20–25°C)

• 

  Ortega's cory

  Hoplisoma ortegai

  Freshwater
  2 in (5 cm) · 16 gal (60 L)73–81°F (23–27°C)

• 

  Ortega's dwarf cichlid

  Apistogramma ortegai

  Freshwater
  2.6 in (6.5 cm) · 16 gal (60 L)75–82°F (24–28°C)

• 

  Ourastigma cory

  Corydoras ourastigma

  Freshwater
  2.6 in (6.5 cm) · 20 gal (75 L)75–82°F (24–28°C)

• 

  Owroewefi guianacara

  Guianacara owroewefi

  Freshwater
  5.1 in (13 cm) · 66 gal (250 L)77–84°F (25–29°C)

• 

  Oxyrhynchus hap

  Hemitilapia oxyrhynchus

  Freshwater
  7.9 in (20 cm) · 119 gal (450 L)75–81°F (24–27°C)