Oh! So here we are at the letter O. This is another letter which doesn’t have as many fish as some of the others, but it didn’t stop us from picking our 5 favorites and writing a bit more about each of them.
We’ve got fish from the ocean, orange fish and even an obese fish in our list, so we’re super sure you’re going to enjoy discovering all of the fish that start with O.
Both the common names and scientific names are provided so you can discover even more about these fabulous finned fish. Scientific names are in brackets… the words that look a little like gobblygook!
Table of Contents
Our Top 5 Fish Names Beginning with Letter O
We’ve picked 5 awesome fish to demonstrate how cool fish that start with O can be. From stingrays to cichlids, there’s definitely something for everyone in our top five.
If you have a favorite from our choices or have your own, then comment below!
Ocellated Freshwater Stingray (Potamotrygon motoro)
The Ocellated Freshwater Stingray is a spotty ray which lives in rivers, including the Amazon, Orinoco and Mearim basins. These rays can grow to be longer than 1.5 ft and they can actually be a little dangerous. They are sometimes kept in aquaria, but they are quite specialist and you would need a very large tank to house an Ocellated Freshwater Stingray.
We love their yellow spots, which also give them another common name – Peacock-Eye Stingray.
Ocellated Lamprologus (Lamprologus ocellatus)
Another ocellated fishy in our hand-picked top 5, the Ocellated Lamprologus. This is a type of cichlid that actually likes to live in a shell sometimes. They can get a little aggressive when they’re defending their home. If you keep a shell-dwelling Lamprologus, you should provide them with a choice of empty snail shells and make sure there are enough for each fish of this species.
Because these fish tend to live on the bottom of the tank, they should be fine to be paired with fish that dwell towards the middle or top of the tank. Males should be kept with multiple females to avoid them aggrivating a single female and stressing her out.
Opaline Gourami (Trichogaster trichopterus)
The Opaline Gourami sounds like a mythical gemstone that brings luck and magic to whoever finds it. But it is in fact a lovely type of fish. Gourami are quite a popular fish amongst aquarists and they do make really great pets.
Opaline Gourami are relatively peaceful and can live well with other fish but you should avoid mixing them with fish that tend to nip fins – Gourami are known for their extended ventral fins which would prove too much of a temptation for some tank mates.
Opaline Gourami can actually change color depending on their mood – just like a mood ring! How cool is that?
Oscar (Astronotus ocellatus)
These big bad boys are very popular fish to keep and despite its slightly scary appearance, this cichlid isn’t all that aggressive. They do however, like to dig into the substrate a little, so avoid heavily decorated tanks when keeping an Oscar as it could end up getting ruined.
When it comes to tank mates, you should avoid putting Oscar cichlids in with smaller fish, as they are carnivorous and may see these little fishies as food. Oscars can be very greedy and may even beg at the side of the tank when they see their owner approaching!
Otocinclus (Otocinclus affinis)
The Otocinclus is a type of catfish that also go by the name of Oto, Otto Cats, Dwarf Suckermouth or Algae Scrapers. As you may have guessed from that last name, these little catfish like to scrape algae from rocks and the side of your tank – perfect for keeping your aquarium looking tip-top.
Otos are quite delicate fish and can be a little difficult to look after. Once they’re in the tank and settled, they should be fine, but they can tend to die unexpectedly after showing no signs of being ill. But don’t let that put you off, a lucky Otocinclus could be your buddy for over a year!
List of fish names starting with O
Keep on reading to discover more fish beginning with O and you might even find your own top 5! If you’ve got any of the fish in our lists in your aquarium, let us know in the comments below.
Freshwater fish beginning with O:
- Obese Synodontis (Synodontis obesus)
- Obliquidens Hap (Haplochromis obliquidens)
- Obscure Snakehead (Parachanna obscure)
- Ocellated Loach (Acanthocobitis urophthalmus)
- Ocellated Shell-Dweller (Neolamprologus kungweensis)
- Ocellated Synodontis (Synodontis ocelli fern)
- Odynea Pimelodid Catfish (Pimelodella chagresi odynea)
- Old World Knifefish (Chitala ornata)
- One-Gilled Swamp Eel (Ophisternon bengalense)
- One-Lined Pencilfish (Nannobrycon unifasciatus)
- One-Spot Synodontis (Synodontis notatus)
- Orange Chromide (Etroplus maculatus)
- Orange-Finned Loach (Botia modesta)
- Orange-Lined Cichlid (Melanochromis joanjohnsonae)
- Oregon Chub (Oregonichthys crameri)
- Orfe (Leuciscus idus)
- Oriental Loach (Misgurnus anguillicaudatus)
- Oriental Snakehead (Channa orientalis)
- Ornate Bichir (Polypterus ornatipinnis)
- Ornate Ctenopoma (Ctenopoma ansorgii)
- Ornate Fin Nipper (Ichthyborus ornatus)
- Ornate Pimelodus (Pimelodus ornatus)
- Oxeye Herring (Megalops cyprinoldes)
- Ozola Barb (Barilius barna)
Saltwater fish beginning with O:
- Oarfish (Regalecus glesne)
- Ocean Perch (Sebastes norvegicus)
- Ocean Sunfish (Mola mola)
- Oceanic Whitetip Shark (Carcharhinus longimanus)
- Oilfish (Ruvettus pretiosus)
- Oldwife (Enoplosus armatus)
- Olive Flounder (Paralichthys olivaceus)
- Opah (Lampris guttatus)
- Opaleye (Girella nigricans)
- Orange Roughy (Hoplostethus atlanticus)
- Orangespine Unicorn Fish (Naso lituratus)
- Orangestriped Triggerfish (Balistapus undulatus)
- Orbicular Batfish (Platax orbicularis)
- Orbicular Velvetfish (Caracanthus typicus)
- Owens Pupfish (Cyprinodon radiosus)