- Common name: Dwarf Oto
- Scientific name: Otocinclus macrospilus
- Family: Loricariidae
- Sub family: Hypoptopomatinae
- Geographical location: South America
- Size: 3 - 5 cm
- Water conditions: 6.0 - 7.0 pH, 21-26°C
Otos are one of our favourite fish in the planted aquarium. We used to think that bristle nose catfish were perfect for algae eating but we’ve found as they get older they don’t eat much algae at all and are constantly digging up the plants and gravel. Not that otos are only good for algae eating, but they can rid your aquarium of brown algae almost over night! They are sucker mouth catfish and are most often viewed from their underside as they hang on your aquarium glass. This gives a perfect view of their pearly white bellies, showing whether it is time to feed them again or not depending on how plump their bellies are. Before first keeping otos we had only seen pictures on the internet of their underside against the glass and so didn’t know they were spotted brown and slightly hairy on their backs! They are often mistaken for Otocinclus afinis however the macrospilus is a mottled brown colour with a distinct white lateral line running from its nose to its tail. The macrospilus is much more common in the aquarium trade but both species have the common name ‘dwarf oto’ and the afinis has a more golden sheen to it. Otos are best fed spirulina discs and should not be introduced to the aquarium until it is slightly mature with some algae present. They can be a bit shy and prefer to eat just after the lights go out.
All otos being sold at the moment are wild caught with only a handfull of people claiming success in captive breeding. Being wild caught means that most otos, once established, are very robust with good genes. Being a popular and seasonal fish can mean that otos are sometimes hard to source with most being imported via Germany. Otos are very sociable fish and like being kept in groups of at least two. They graze by jumping from leaf to leaf in groups and for this reason are sometimes refered to as little monkeys.
Happy oto watching 