It's a species of Macrognathus; likely Mastacembelus circumcinctus. Not especially common in the UK trade at least, but not exactly unknown either.
The usual comments apply as for other Macrognathus. It's a gregarious, largely non-piscivorous species that needs a sandy substrate, never gravel, but will adapt to a range of water conditions for soft and acidic through to slightly brackish. Keep in a tank with lots of plants, especially floating plants, and don't mix with other bottom feeders except perhaps things like bristlenose plecs that won't compete for food. Needs live foods initially (bloodworms, tubifex, earthworms) but will adapt to wet frozen once settled. Feeds only at night.
Cheers, Neale
