Butterfly Loach

Care at a glance

Overview

The butterfly loach, sometimes sold as the butterfly hillstream loach, is a broad, flat grazer that fans its patterned fins out against rocks and glass. It is social and calm, so keep several together, around five or more, and give them open hard surfaces to work across. They spend the day rasping biofilm and algae, which should be supplemented with sinking wafers, blanched courgette, and small frozen foods once a film builds up. Pair them with peaceful, cool-water fish that share their need for current. A group needs an oxygen-rich tank of about 95 liters or larger with strong, steady flow.

In the wild

Beaufortia kweichowensis comes from fast, rocky rivers in southern China, where it clings to stones in shallow, sunlit runs. These are subtropical streams, so it prefers cooler water than most tropical fish, roughly 16 to 24 C, with a pH from about 6 to 7.5. Recreate the flow with a powerhead and a strong filter, lay in rounded rocks and cobbles for surfaces to graze, and keep the tank mature so algae and biofilm can establish. High oxygen and cool, clean, moving water are the keys to keeping this fish healthy.

Good to know

Beaufortia kweichowensis is a member of Gastromyzontidae and grows to around 7.5 cm. Its body is disc-flat and its paired fins wrap outward to form a suction surface, an adaptation for holding onto rock in strong current rather than for swimming in open water. It lacks the erectile eye spine seen in botiid loaches. Breeding is essentially unrecorded in home aquaria, though it is a scatter spawner in the wild, and most stock in the trade is wild collected.

Did you know

Seen from above, the butterfly loach spreads its rounded, dark-spotted fins flat against the rock, and that wing-like outline is what earns it the butterfly name. The pattern also breaks up its shape against dappled streambed stones.

Related species

• 

  Red hillstream loach

  Beaufortia leveretti

  3.1 in (8 cm)24 gal (90 L)64–75°F (18–24°C)

• 

  Tiger hillstream loach

  Sewellia lineolata

  2.6 in (6.5 cm)25 gal (95 L)68–75°F (20–24°C)
• Spotted hillstream loach

  Gastromyzon punctulatus

  2.6 in (6.5 cm)20 gal (75 L)68–75°F (20–24°C)
• Panda loach

  Yaoshania pachychilus

  2.8 in (7 cm)20 gal (75 L)64–75°F (18–24°C)

• 

  Borneo hillstream loach

  Gastromyzon ctenocephalus

  1.6 in (4 cm)20 gal (75 L)68–75°F (20–24°C)
• Chinese butterfly loach

  Pseudogastromyzon cheni

  2.4 in (6 cm)20 gal (75 L)64–75°F (18–24°C)