Annamia Thuathienensis

Datasheet

General Description

Annamea Thuathienensis, a member of the Gastromyzontidae family, is a loach species native to central Vietnam. It has a maximum size of about 10.0 cm and is characterized by a depressed body shape, elongate lower caudal-fin lobe, and distinctive unbranched rays in the pectoral and pelvic fins. Little is known about A. thuathienensis, and it is considered a species inquirenda.

Aquarium Setup

To create a suitable environment for Annamia species, a tank setup resembling their natural habitat in riffles and rapids is crucial. This includes a substrate of gravel, sand, and water-worn rocks, along with driftwood roots or branches. While most aquatic plants struggle in such conditions, hardy varieties like Microsorum, Bolbitis, or Anubias can be attached to the decor. Bright lighting aids in aufwuchs growth for grazing. Maintaining spotless water, high oxygen levels, and water movement (10-15 times per hour) is essential, requiring powerheads or airstones. Regular water changes of 30-50% volume are crucial for their well-being.

Behaviour

Annamea loaches are generally peaceful but prefer larger aggregations. When kept singly or in smaller numbers, they tend to exhibit shy behavior. Their tank mates should be chosen carefully due to their specific environmental requirements. Suitable companions include various species such as Barilius, Opsarius, Rasbora, and certain catfish genera but may squabble with certain loaches.

Feeding and Diet

Traditionally considered micropredators, these loaches have been found to specialize in grazing on cyanobacteria, particularly in swift-flowing streams like the Duc My River in central Vietnam. Offering a varied diet is recommended, including Spirulina-infused foods, chironomid larvae, Tubifex, Artemia, and allowing aufwuchs growth on tank surfaces. Emaciated specimens may require special care and sustained feeding to regain strength before introducing them to other species.

Reproduction & Dimorphism

Although presumed to be seasonal spawners in their natural habitat, breeding Annamia in captivity has not been documented. Sexually mature females are likely to be slightly larger and fuller-bodied compared to males, indicating possible sexual dimorphism within the species.

Habitat and Distribution

Annamea Thuathienensis is described from the Bô River in Thua Thien-Hue Province, central Vietnam, with no additional records of its distribution. These loaches inhabit shallow, swiftly-flowing stretches of streams and rivers characterized by crystal clear water, rocky substrates, and preferentially live in rapids where they graze on cyanobacteria. Juveniles occupy shallower waters feeding on organic detritus while adults feed selectively on encrusted cyanobacteria in rapids.