Spotted Hillstream Loach

Geographic Origin and Biotope: Endemic to Borneo (Sarawak, Brunei). Shares mostly the habitats of the catenus cousins: wild mountain streams with smooth stony bottoms, roaring waterfalls and freezing high-altitude temperatures.

Taxonomy and Morphology: Spotted Hillstream Loach / Spotted Borneo Sucker (Gastromyzon punctulatus). Famous stream Balitorid. It has a flattened suction-cup discoid body, designed to reduce the friction of currents by 100%. They breathe from tiny dorsal gill vents.

Social Behavior: Sociable with each other. Absolutely comical: they defend the pebble they graze on by covering or bumping away opponents by pushing them, in totally harmless quarrels (they do not have real armor like Loricariids).

Coloration and Sexual Dimorphism: Unlike catenus (striped/reticulated), punctulatus presents, on a dark or deep olive green base, hundreds of very fine yellowish-white round spots on the head, which fade in the middle of the body. Tail splashed with blue or brick red.

Aquarium Setup: A Hillstream Tank is needed. Filter that moves titanic litrages (up to 20 times the tank capacity hourly). No heater. Oxygen-rich water, banks with large round flat stones to expose to the light of the led tube.

Diet and Feeding: Specialized grazer. The ideal tank has stones covered with "Aufwuchs" and patina algae. Integration with special jellies for fish (Repashy), blanched zucchini or vegetable wafers that do not crumble quickly with the passage of the current.

Water Quality: They hate extreme heat. If the aquarium in summer goes to 28-30 degrees (82-86°F), oxygen saturation levels will collapse and the fish will slide off the glass dead in a few hours.

Compatibility and Tankmates: Due to its very special need to have a cold water washing machine, it tolerates as companions only robust stream fish (Barbus, Danio kyathit, Botia dario or Rhinogobius). Never pair with pufferfish, labeos, discus or slow cyprinids.

Aquarium Reproduction: Females swell if filled with eggs in the warm months; the male digs a tiny crevice among the cracks to fertilize them. Joyful but purely incidental event in a home aquarium.

Risks and Diseases: Malabsorption (death by starvation) in overly clinical and clean tanks lacking biological film (encrusting algae). In addition, medications (especially malachite green) block their skin pores.