Matt Clarke looks explains how to tell the difference between Devario maetaengensis and its imposter shanensis.
Common name: Tiger danio
Scientific name: Devario maetaengensis Fang 1997
Origin: D. maetaengensis is found in northern Thailand, not far from the border with Myanmar, with the type locality listed as the Metang River (a tributary of the Me Nam Ping). Kottelat has also found the species in a tributary of the Nam Mae Taeng. The related D. shanensis is found further north in central Myanmar.
Size: When adult, maetaengensis is quite a stocky 8cm/3" in length.
Water: Like most danionins, these are hardy, adaptable little fish. Neutral or slightly acidic water is fine. Most danionins prefer the temperature a little lower than other tropicals. 20-25 C is adequate.
Diet: Flakes supplemented by frozen bloodworm, daphnia and cyclops.
Aquarium: Ideal for the community tank, despite its relative rarity in the trade. Keep a shoal of six or more in a 90cm/36"+ aquarium with plenty of free-swimming space and a nice current. They're fast swimmers and will mix peacefully with most other fishes. Dead easy to keep, even for newcomers.
Sexing: Easy. Females become deeper and plump with eggs when ready to spawn. Males are slimmer and generally a little more colourful.
Breeding: According to PFK contributor Pete Cottle, who was probably the first to breed this species in the UK, it's now being commercially produced in Germany by Fischhaus Zepkow. Pete used a mop-technique to spawn these. You can read his breeding report on the Strood Aquarist Society website: www.stroodaquarist.co.uk
Identification: This species is very easy to confuse with Devario shanensis - even the experts get the two fish muddled up, and the original specimens used to describe maetaengensis had been mis-identified as shanensis. The differences between the two are very subtle, so if you don't know the collection locality, you could get them mixed up. Both species are on sale here. D. maetaengensis tends to be a little more copper-coloured, stockier, with a greater body depth and a stouter caudal peduncle than shanensis. According to collector Kamphol Udomritthiruj the number of bars on the flanks is variable, and a single fish can have a different number of bars on each side. The original description of maetaengensis says that shanensis has a cleithral spot which is absent in maetaengensis. D. maetaengensis also has a complete lateral line with 31-35 pored scales, while shanensis has an incomplete lateral line with 23-25 scales. Later work by Fang also contradicts this and says that the lateral line of shanensis can be either complete or incomplete and gives different numbers of pored scales. Sadly, the chances of you being able to examine these characters on a moving danio are pretty slim... You can find more out about this species on Pete Cottle's excellent new danionin website: www.danios.info
Availability: This species is one of the "new" danionins to have entered the trade in the past couple of years. It has been becoming increasingly common in recent months, but it's still a rarity in the trade. We spotted these on sale at Frisby Aquatics in Hull in November.
Price: Expect to fork out around 3.00-4.00 for one of these.