El otocinclusThe glass cleaner, commonly known as the window cleaner, is one of the most prized fish by aquarium hobbyists thanks to its excellent algae-eating abilities and calm demeanor. Native to South America, especially regions such as southeastern Brazil, the Mato Grosso rainforest, and rivers in Colombia, this small catfish belongs to the Loricariidae family and stands out not only for its ability to clean aquarium glass, but also for its gregarious behavior and easy adaptation to well-planted community aquariums.
Natural Habitat and Geographic Distribution
It is common to find different species with very similar morphologies, which often leads to confusion among hobbyists. For example, O. vittatus y O. affinis They are only clearly differentiated by their area of distribution. Among the most popular species is also the O. cocama (Otocinclus zebra), known for its striking vertical stripes.
Physical Characteristics and Morphology
The body of the Otocinclus is elongated, small and slightly flattened on the belly. Adults measure between 3 and 5 cm depending on the species, while their weight rarely exceeds 0,3 grams. The head has a suction cup mouth, perfect for adhering to glass, plants, and decorations while feeding. This morphology allows it to survive in fast-moving waters, holding firmly to surfaces to avoid being swept away by the current.
The typical coloration consists of brown, gray, or gold tones on the back, with a dark lateral band that runs from the snout, past the eye, and ends at the base of the caudal fin. The belly is light, usually white or yellowish. The pectoral, ventral, and dorsal fins are transparent or semi-translucent, providing camouflage and extra security in their surroundings.
A relevant adaptation of some Otocinclus is their limited ability to breathe air directly from the surface in cases of hypoxia. This gives them an advantage in habitats where oxygen can fluctuate.
Sexual Differentiation (Dimorphism)
The differentiation between males and females in Otocinclus is very little obviousFemales are generally slightly larger and wider, especially ventrally and during the breeding season. Males tend to be more slender, but these differences are only noticeable when comparing several adult specimens. There are no notable variations in fin coloration or shape between the sexes.
Behavior and Compatibility in the Aquarium
Otocinclus is known for its peaceful and shy natureIt rarely presents behavioral problems, making it an excellent choice for community aquariums. It is a gregarious fish by nature, so it is recommended to keep it in schools of at least 5-6 individuals. Living in a group reduces stress and enhances natural behaviors., like shepherding together through decoration and glass.
Regarding compatibility, Otocinclus can coexist perfectly with small, peaceful species such as tetras, cardinalfish, corydoras, danios, mollies, guppies, rasboras, or invertebrates such as snails and shrimp. It's important to avoid large, territorial, or aggressive fish, such as large cichlids, as they could prey on them or cause excessive stress.
During the day, they usually remain attached to leaf and glass surfaces, resting or feeding. They are most active at dusk or during low-light hours, when they move in search of food and systematically search the entire aquarium.
Food and Nutritional Requirements
Otocinclus is mainly herbivore and biofilm consumerIn nature, their diet consists almost entirely of soft algae, diatoms, biofilm, small microorganisms, and plant debris they extract from logs, stones, and plants. This specialization makes them effective allies for controlling algae growth in aquariums.
However, in a home aquarium, there is often not enough algae to support several Otocinclus specimens, especially in new or extremely clean aquariums. Therefore, it is essential supplement your diet regularly with:
- Seaweed wafers or vegetable tablets for bottom-dwelling fish
- Blanched fresh vegetables such as zucchini, cucumber, spinach, or romaine lettuce
- Spirulina wafers The future of television is here
- In specific cases, peeled and crushed peas, or small portions of powdered food for fry
It is recommended to remove any remaining plant food after 24-48 hours to avoid water contamination. Supplemental feeding should be done several times a week, adjusting the frequency according to the amount of algae present in the aquarium and the size of the Otocinclus group. A rounded belly is a sign of good nutrition.
Some newly acquired Otocinclus are slow to recognize commercial foods, especially wild-caught ones; patience and variety are key to their adaptation.
Aquarium Conditions: Parameters, Setup and Maintenance
To ensure the well-being of Otocinclus it is essential recreate an environment similar to its natural habitatThe key factors to consider are:
- Minimum volume: 40-60 liters for a group of 5-6 specimens, although a larger space facilitates the maintenance of larger colonies.
- Plant density: It is essential to have abundant natural plants (Anubias, Echinodorus, Cryptocoryne, mosses), which provide shelter, surfaces for biofilm growth and resting areas.
- Substratum: Fine sand or soft gravel; avoid rough substrates that can damage the stomach and mouth.
- Decoration: Smooth logs, roots, and stones provide hiding places and promote the growth of algae, tannins, and microorganisms.
- Filter: Powerful and well-developed, with a flow rate that renews the aquarium's volume about three times per hour, ensuring oxygenation and current without generating excessive stress.
- Temperature: Between 22 and 26°C, without exceeding 27°C.
- pH: Slightly acidic to neutral, between 6.0 and 7.5.
- Hardness: Between 5 and 15 dGH.
- Nitrates: Less than 50 mg/L.
The water should always be clean and well oxygenated; Otocinclus are sensitive to sudden changes in parameters and the accumulation of contaminants such as nitrites and ammonia. Therefore, its introduction into very young or unstable aquariums is not recommended. Perform regular partial water changes of between 20 and 30% every two weeks to maintain the overall health of the ecosystem.
Suboptimal conditions can lead to health problems and sudden mortality after introduction, a critical phase in the adaptation of Otocinclus to the home aquarium.
Reproduction and Breeding in Aquarium
La reproduction of Otocinclus In a home aquarium, this challenge is only achievable if you have a mature, healthy group with optimal water conditions and a varied diet. Spawning usually occurs spontaneously when the environment and diet are ideal, although it can be stimulated by a slight drop in temperature simulating the rainy season.
Courtship typically consists of one or more males chasing the female until she accepts, adopting the familiar "T-position" typical of Loricariids. The female lays adhesive eggs in small numbers (20 to 75 depending on size and species) on leaves, glass, and sometimes in the filter. The parents do not provide parental care for the eggs and may consume them if they remain in the general aquarium.
The eggs hatch in 2–4 days, depending on the temperature. The fry initially absorb their yolk sac, then must be fed infusoria, microplankton, and, gradually, newly hatched brine shrimp nauplii, microworms, and finely ground vegetables. A mature rearing tank with biofilm on the walls is essential for their survival.
The half-life of Otocinclus under optimal conditions is 3 to 5 years, although there are reports of specimens that live longer than this. The price per specimen is around €2-4, depending on the species and size.
Main Care, Disease Prevention and Useful Tips
- Avoid overeating and eliminate food scraps vegetable before they decompose.
- Do not mix Otocinclus with aggressive species Do not introduce these fish into newly set up or unstable aquariums.
- Regularly monitor your health status: A sunken abdomen, inactivity, or rapid breathing may be symptoms of illness or lack of food.
- Otocinclus can be susceptible to parasites and fungi, especially during adaptation. Ensure proper quarantine and regularly monitor water parameters.
The Otocinclus is not only an effective algae cleaner, but also a fascinating fish due to its gregarious behavior and ability to coexist peacefully in community and planted aquariums. Proper maintenance, a complete diet, and the correct selection of tank mates are key to enjoying the presence and observation of these tiny aquarium "engineers."
When the Otocinclus fully adapts and lives in optimal conditions, your aquarium will look not only clean and healthy, but full of life and natural harmony thanks to the discreet but tireless work of this peculiar South American catfish.
