Matt Clarke looks at a rarely seen midwater swimming loach from Lake Inle in Myanmar that has recently been imported into the UK.
Common name: Inle loach
Scientific name: Yunnanilus brevis (Boulenger, 1893)
Origin: Museum records show that the species is most common on the western shores of Inle Lake in Myanmar (formerly Burma), part of the Salween River drainage. According to Kotellat the species has also been recorded from the He-Ho Plains in the southern Shan States of Myanmar.
Size: Females are larger than males and reach a stocky 7cm, while males are slimmer and a centimetre or two shorter.
Diet: This is a midwater feeding loach which seems to have a liking for zooplankton, such as daphnia and brineshrimp. It takes flakes readily too.
Water: Precise conditions not known, but these are doing fine in unadjusted Cambridgeshire tapwater.
Aquarium: This is a peaceful midwater fish that remains active for most of the day and actively feeds on items in the water column. I keep a group of these alongside some danio-like Inlecypris auropurpureus, also from Inle Lake, as well as various small danionins.
Sexing: I believe that this species is sexually dimorphic and sexually dichromatic. My males are smaller and have a black longitudinal stripe, while the females have a marbled pattern of grey-blue striations and spots. Loach expert Graeme Robson has a collection of Yunnanilus from the same batch as these and has managed to get his females to show stunning red colouration on their caudal fins. Mine currently only show a pale orange in their fins. According to Gerhard Ott, the editor of German magazine VDA Aktuell, who took these photographs, males also have a subocular flap. This is something that's seen in quite a few nemacheiline loaches, but you need a magnifying glass or macro lens to see this.
Breeding: Few fishkeepers have kept Yunnanilus so little is known about their reproduction. The females become plump every few weeks but no spawnings have been observed. Both sexes seem to develop a slightly curved spine. This appears to be a normal trait of the species.
Notes: This fish was originally described as Nemacheilus brevis by Boulenger back in 1893, but it's now considered a member of the nemacheiline genus Yunnanilus. Others have placed the fish in Eonemacheilus and Noemacheilus.
Identification: There is very little information available on any of the Yunnanilus species. My fish appear to resemble the Y. brevis shown on FishBase and those collected by exporters working on Inle Lake.
Related species: Like most people, I had only heard of Y. brevis, however, there are in fact a total of 27 species in the Yunnanilus genus: Y. altus; Y. analis; Y. beipanjiangensis; Y. brevis; Y. caohaiensis; Y. chui; Y. cruciatus; Y. discoloris; Y. elakatis; Y. forkicaudalis; Y. longibulla; Y. longidorsalis; Y. macrogaster; Y. macroistainus; Y. macrolepis; Y. nanpanjiangensis; Y. niger; Y. nigromaculatus; Y. obtusirostris; Y. pachycephalus; Y. paludosus; Y. parvus; Y. pleurotaenia; Y. pulcherrimus; Y. sichuanensis and Y. yangzonghaiensis. Many of these come from China and I'm unaware of imports of anything other than brevis.
Availability: I purchased a group of these fish from The Waterzoo in Peterborough in April this year. It's the first time I have seen any Yunnanilus species on sale in the UK, but I am told that BAS has imported the species in the past. These fish were on sale as Nile loaches - clearly the supplier thought Inle was spelt incorrectly. There are no loaches found in the Nile as far as I am aware! Maidenhead Aquatics @ Peterborough received a large shipment of these fish after this article was published in the print magazine.
Price: These were very cheap given their rarity at just £2.00 each.
This article was first published in the October 2006 issue of Practical Fishkeeping magazine.