Matt Clarke looks at the recently described Vietnamese minnow, Tanichthys micagemmae.
Common name: Vietnamese minnow, Dwarf Vietnamese cardinal
Scientific name: Tanichthys micagemmae
Origin: Ben Hai river, Central Vietnam.
Size: Tiny at just 2.5cm/1", or so.
Water: Dr Jrg Freyhof (who described it) tells me that the water wasn't tested at the collecting site. It appears to do well in neutral, lukewarm water.
Diet: Not known. Probably feeds on small aquatic invertebrates and insect larvae, so Daphnia and finely crumbled flake should be OK for aquarium fish.
Aquarium: These fish usually live in shallow, fast-moving water over a sandy bottom. Add an oversized power filter to make them feel at home and keep the water better oxygenated.
Sexing: Like albonubes, male micagemmae have tiny raised tubercles under the eye during the breeding season. Their dorsal and anal fins are slightly longer and they are grey below the lateral stripe when spawning.
Breeding: Probably not difficult. T. albonubes is a very easy to breed egg-scatterer and is mass produced.
Notes: This species was described by Drs Jrg Freyhof and Fabian Herde in Ichthyological Exploration of Freshwaters back in 2001. "Micagemmae" translates roughly as "sparkling gem".
Similar species: The very common T. albonubes is the only other common species in this genus. T. thacbaensis was described in 2001. There are several different wild forms of albonubes, as well as a number of aquarium strains, including the Comet, long-finned and a very colourful yellow form with blood red fins. The fish sold in the shops as T. lini are, in fact, a form of albonubes from Hong Kong, not the White Clound mountain. (Aphyocypris (Hemigrammocypris) lini is a different fish).
Identification: T. albonubes is brown below the lateral stripe while micagemmae is paler, often with tiny dark spots. The two black and white lateral stripes in micagemmae are of roughly equal width. The black stripe is about 0.9-1.8 times wider than the white stripe here, while in albonubes it's 0.3-0.6 times as wide. The stripe is also lower down on micagemmae than in albonubes.
Availability: We've only seen a handful of these on sale in the UK. These were on sale at Sweet Knowle Aquatics, Warwickshire (01789 450036).
Price: Rare, so not cheap at 3.95.