Bumblebee Otocinclus

Rhinotocinclus isabelae, commonly known as the Bumblebee Otocinclus, is a small South American loricariid catfish native to central Brazil, where it is found in clear, shallow streams of the upper Paraguay River basin, particularly in the Mato Grosso region. These habitats are typically well oxygenated with gentle to moderate flow, sandy or fine gravel substrates, and abundant submerged vegetation, grasses, and marginal plants. Water clarity is usually high, and the species spends much of its time grazing on surfaces exposed to light.

Adult Bumblebee Otocinclus remains small, generally reaching about 1.25 to 1.5 inches in length. The body is compact and streamlined with a low profile, well suited to clinging to plant leaves and hard surfaces. Coloration is distinctive, featuring a pale tan to olive base with a bold, dark lateral stripe running from the snout through the eye to the caudal peduncle, giving rise to the “bumblebee” common name. Fine mottling and patterning along the body provide camouflage among plants and substrate. Their understated appearance and constant activity make them appealing in naturalistic aquariums.

A tank of at least 15 to 20 gallons is recommended for a proper group. Bumblebee Otocinclus is a social species and should be kept in groups of six or more to display natural behavior and reduce stress. The aquarium should be well planted, with plenty of broad-leaved plants, driftwood, and smooth surfaces for grazing. Gentle to moderate water movement is ideal, along with good oxygenation and stable conditions.

Water parameters should reflect their native clearwater streams. Temperatures between 72 and 78 degrees Fahrenheit are appropriate, with a pH range of roughly 6.0 to 7.5 and soft to moderately soft water. Stability and water quality are critical, as this species is sensitive to deteriorating conditions and sudden changes. Regular water changes and low nitrate levels are important for long-term health.

Feeding Bumblebee Otocinclus requires attention beyond relying on natural algae growth. In the wild they graze on biofilm, algae, and microorganisms. In the aquarium they should be offered blanched vegetables such as zucchini or spinach, algae wafers, and high-quality sinking foods designed for herbivorous fish. Established tanks with natural biofilm are strongly recommended, as newly set up aquariums often lack sufficient grazing resources.

Temperament is peaceful and unobtrusive. Bumblebee Otocinclus does well in calm community aquariums with other small, non-aggressive fish that share similar water requirements. Suitable tankmates include small tetras, rasboras, pencilfish, and other gentle species. They should not be housed with large or aggressive fish that may harass them or outcompete them for food.

Breeding in captivity is rare and not well documented. Like many small loricariids, they are believed to scatter eggs on plants or hard surfaces without parental care. Most individuals available in the aquarium trade are wild collected.

Rhinotocinclus isabelae, the Bumblebee Otocinclus, is a subtle, hardworking algae grazer best suited for mature, well-planted aquariums with stable water conditions. Its small size, peaceful nature, and constant grazing behavior make it an excellent addition to carefully maintained community tanks where delicate species are appreciated.