Matt Clarke looks at the Taiwan horse mouth, Candidia barbata, an unusual import for the coldwater aquarium.
Common name: Taiwan horse mouth, Barbel’s stripe minnow
Scientific name: Candidia barbata (Regan, 1908)
Origin: Endemic to Taiwan. These are found in most northern river systems in Taiwan from the western slope and Central Mountain Ridge to the Kaoping River in the sound. They are also present in Lake Candidius in Nantou County.
Size: Reaches a maximum size of 15cm/6”, but typically around 10cm/4”.
Water: A coldwater fish. Air temperatures in the area range from 11.5-23.7C.
Diet: Feeds mainly on surface dwelling terrestrial insects and aquatic invertebrates that live among the bottom rocks.
Habitat: These fish, which are closely related to Zacco, are said to prefer slow-flow pools in the upper reaches of clear, coolwater mountain creeks at elevations of 500-1200m.
The species only lives in clean water areas (it is used as a biological indicator species in Taiwan) so good water quality is essential. Flow rates in the habitat range from still to 4.85m3 sec, with an average of 0.75m3 per second. The water ranges in depth from 2-61cm deep and the fish live in streams from 1.7-10.5m wide.
Aquarium: Go for a tank of at least 90cm/36”, ideally 120cm/48”. Add a powerful filter and furnish with sand, gravel, water-worn rocks and the odd piece of driftwood. They live alongside Varicorhinus barbatulus, Crossostoma lacustre, Rhinogobius candidianus, Cobitis sinensis and Acrossocheilus paradoxus. Some of these have recently appeared in the shops, too.
Sexing: Males develop larger spawning tubercles on the snout and have a red patch on the lower portion of the gill cover from the corner of the mouth to the rear of the operculum. They are also more brightly coloured than females, with red pectoral fins and dark lines in the dorsal.
Notes: Until recently, this species (sometimes referred to as Candidia barbatus or Opsariichthys barbatus) was the only species in the Candidia genus, but last year scientists described C. pingtungensis from the Fongkang River in Pingtung, southern Taiwan.
Identification: Candidia barbatus should have a uniform grey body with a longitudinal blue-black stripe which is interrupted and irregular towards the head end, compared to a broad silvery white stripe on the dorsal half and a deep black stripe below it in C. pingtungensis. C. barbatus has one pair of barbels and C. pingtungensis has more than one pair. There are also differences in the number of scales.
Availability: It’s the first time I’ve seen this species on sale in the UK. These were photographed at Wildwoods in Middlesex.
Price: On sale for £xx.xx each.