The Otocinclus Affinis, also known as the “Dwarf Sucker Catfish,” is a small freshwater fish that is part of the Loricariidae family. It is a small fish with a maximum size of around 2 inches (5 cm) and a slender body shape. They have a light brown or olive-green body coloration with a white or cream-colored underside. These fish have a sucker-like mouth, which helps them to cling onto surfaces in the aquarium and scrape off algae. They have a flattened head with a pair of barbels near their mouth, which are used for sensing food and the environment.
Otocinclus affinis is an excellent algae eater. They are known for their ability to clean algae off of aquarium glass, plants, and decorations. However, it is important to note that they should not be relied upon as the sole method of algae control in an aquarium. A well-maintained tank with proper lighting and water parameters will help to keep algae growth under control, and the addition of Otocinclus affinis can help to supplement that effort.
Natural Habitat :
The natural habitat of Otocinclus affinis is typically found in slow-moving or still waters, such as streams, small rivers, and ponds in South America’s Amazon River basin. The environment in which they live is characterized by dense vegetation, including areas with aquatic plants such as water lettuce and water hyacinth.
The water in their habitat is usually clear and has a pH between 6.5 and 7.5. The temperature range of their habitat is between 72-82°F (22-28°C). The substrate in their habitat is typically made up of sand, gravel, or mud, and there are often areas with rocks and other structures that provide shelter.
The vegetation in their natural habitat is important to them as it provides both food and shelter. The dense vegetation also helps to maintain the water quality by providing oxygen and filtering impurities from the water. The Otocinclus affinis is also known to use the vegetation as a place to rest or hide from predators.
Overall, the natural habitat of Otocinclus affinis is a peaceful, tranquil environment with clear water and abundant plant life. It is an ecosystem that supports a diverse range of organisms, including fish, invertebrates, and other aquatic life.
Keeping Otocinclus Affinis Healthy:
The Otocinclus Affinis is a relatively hardy fish and is a good choice for beginner fish keepers. However, it is important to maintain good water quality, as poor water conditions can be harmful to this fish. A pH range of 6.5-7.5 and a temperature range of 72-78°F (22-26°C) is recommended. They prefer soft to moderately hard water with a low to moderate flow.
Special Requirements and Feeding:
The Otocinclus Affinis is an herbivorous fish that feeds mainly on algae and other plant matter. It is important to provide them with a well-balanced diet that includes both algae-based foods and occasional fresh vegetables. Supplementing their diet with sinking pellets or wafers is also recommended. Additionally, it is recommended to provide hiding places and plants for the fish, as well as occasional vegetable-based treats.
Suitable Tank Mates:
Otocinclus Affinis is a peaceful fish that can be kept with a variety of other peaceful fish, such as tetras, rasboras, and other small catfish species. However, it is important to avoid keeping them with larger or more aggressive fish, as they can be easily outcompeted for food and may become stressed.
Sexual Dimorphism:
Otocinclus affinis does exhibit sexual dimorphism, which means that males and females have different physical characteristics.
In general, male Otocinclus affinis tend to be smaller and slimmer than females, while females are larger and rounder. The easiest way to distinguish between males and females is to observe their genital papilla, which is a small protrusion located near the anus. In males, the genital papilla is thin and pointed, while in females, it is thicker and rounder.
During breeding season, male Otocinclus affinis may also develop small, comb-like structures known as odontodes on their pectoral fins. These structures are used by males to stimulate females during courtship, and they typically disappear once breeding season is over.
Overall, while the differences between male and female Otocinclus affinis are relatively subtle, they can be observed through careful observation of their physical characteristics, particularly the shape and size of the genital papilla.
Breeding Otocinclus Affinis:
Breeding Otocinclus Affinis in a home aquarium can be challenging, as there is no known way to sex the fish externally. They require a mature, heavily planted tank with plenty of hiding places and low to moderate lighting conditions. The breeding process is often initiated by a sudden change in temperature or water chemistry. Once the eggs are laid, they will hatch in approximately 3-4 days.
Distribution:
This fish is native to South America, specifically in the Amazon basin and the Orinoco River in Colombia, Venezuela, and Brazil. It can also be found in other areas of South America, including Ecuador and Peru. Otocinclus Affinis is now available as a captive-bred line-bred strain, making them stronger and more resistant than cheaper wild-caught specimens.
Summary:
The Otocinclus Affinis is a small, peaceful, and hardy fish that is a great addition to a community aquarium. It is important to maintain good water quality and to provide a well-balanced diet that includes both algae-based such as algae wafers or pellets. Otocinclus Affinis can be kept with a variety of other peaceful fish and prefer soft to moderately hard water with a low to moderate flow. Though breeding them can be challenging, the Otocinclus Affinis is a popular and rewarding species for many fish keepers.


Dawn Aitchison (verified owner) –
Cutest little fellas. Quickly got to work on suckling onto the tank 😊
Raymond Ward (verified owner) –
Bought 10 of these and they all seem to have settled in well, straight away feeding on the algae in there tank. Great packaging and a super service. Many thanks
Jane talbot (verified owner) –
Super little guys, started cleaning already, packaged well and great service
Kitchen Aquarium –
I added six Otos to join the three I already had, and they’re thriving together. All arrived healthy, lively, and clearly very well cared for. They got to work straight away and have been a delight to watch. Top-notch quality from Abyss once again!
Liam (verified owner) –
All arrived very healthy and active! The ones I received were actually O. macrospilus species which from my experience are very robust. Beautiful fish and I will be ordering again. Thank you!
Adam (verified owner) –
Ordered 22 of these little cleaners. All 22 alive and extreamly healthy, packaged was the best I’ve had from any of the online suppliers I’ve purchased from in the past.
Anne Selby (verified owner) –
Order 2 to add to a smaller tank with a pair, these are youngsters but perfectly healthy and active. Excellent service and quality fish.
ron.sykes7.rs (verified owner) –
i bought 6 of these from the shop in December, they have been little cleaning machines and i decided to get a few more they arrived yesterday, packaged well and great service, thank you, they got to work with the others immediately..