Hypoptopoma elongatum

Hypoptopoma elongatum is a member of a small genus of Amazonian loricariids that are morphologically and behaviourally distinct from the typical bottom-dwelling pleco or otocinclus. The Hypoptopoma are characterised by their laterally placed eyes and flattened bodies, and they spend a significant proportion of their time free-swimming in midwater rather than adhering to substrate — an unusual trait within Loricariidae. H. elongatum is the most slender species in the genus, with a notably elongated body profile.

In the wild, Hypoptopoma elongatum occurs in the Amazon River system and its major tributaries, where it forages over submerged wood, leaf litter, and aquatic vegetation. Unlike Otocinclus, which clings continuously to hard surfaces, Hypoptopoma species swim actively and graze more intermittently, giving them a different behavioural character in the aquarium. Their diet consists primarily of algae, biofilm, and fine organic matter.

For aquarists, H. elongatum is a rewarding and unusual choice that provides both algae management and midwater visual interest. Its larger size compared to Otocinclus — reaching up to 7 cm — means it requires a somewhat larger tank and may be less effective at fine-detail algae removal on delicate plant leaves. It is best kept in groups and pairs well with other South American species in a well-planted, dimly lit aquarium.

Water: Soft to moderately hard at pH 5.5–7.0 and 22–27°C; good filtration and regular water changes maintain the pristine conditions this species requires. Tank: 80 litres minimum; provide driftwood, leaf litter, and plants; midwater swimming space is important for this species. Feeding: Algae wafers, blanched vegetables, and fine sinking foods; less reliant on surface biofilm than Otocinclus. Breeding: Not documented in aquaria. Compatibility: Peaceful with all medium-sized community fish; avoid very small nano species that it might disturb.