Matt Ford on a delightful goby that may be having a bit of an identity crisis...
Scientific name: Oligolepis cf. acutipennis (Valenciennes, 1837)
Common name: Sharptail goby
Origin: Valenciennes described O. acutipennis from south-western India, but current records suggest an enormous distribution from South Africa/Madagascar across the Indian Ocean to Sri Lanka, India, Indochina, Indonesia, Papua New Guinea and beyond to various Pacific island states, China and Japan.
Most experts agree that this is highly questionable data and instead there exists a complex of similar-looking but probably different species, hence the cf.
Size: Around 12cm/4.7”.
Water: pH 7.5 – 9.0; GH/KH >15°; temperature 71.6-78.8°F/22 -26 °C. It’s a coastal-dweller which enters freshwater lagoons and estuaries in nature so the water should contain some salt; sg value of 1.002-1.010 being ideal.
Aquarium: Should do well in a larger set-up with decent filtration alongside species like Monodactylus, Scatophagus or Toxotes. A soft, sandy substrate is best as they like to dig. Other décor can include some smooth rocks and driftwood or mangrove roots, while lighting need not be too bright.
Best buy a pair or small group.
Diet: Oligolepis spp. feed mostly on benthic items such as worms and insect larvae, although small fish are also apparently preyed on. Dried foods are normally refused, so you’ll need to offer daily meals of live or frozen bloodworm or Artemia, plus chopped prawn and mussel.
Breeding: They’re cave spawners and, though breeding activity has been recorded in captivity, no young appear to have been raised to adulthood. That’s probably because they require a pelagic marine stage. Males have longer unpaired fins than females.
Notes: This is very unlikely to be O. acutipennis and possibly an undescribed fish. There are only five 'official' species in the genus at the moment but it’s in need of a hefty revision as the name 'acutipennis' is often applied to any similar-looking fish with black spots on the body and a pointed caudal fin.
According to Rainboth (1996) members are characterised by possessing 25-30 lateral line scales, three or four rows of teeth in the upper jaw and a pointed caudal fin longer in length than the head. They lack a membranous crest on the nape and have no fleshy flaps on the inside of the pectoral girdle.
They’re included in the large Gobiidae subfamily Gobionellinae of which the most well known in the aquarium hobby are Brachygobius spp., aka Bumblebee gobies, though some Awaous and Rhinogobius have recently become more readily available.
Availability: These were on sale at Maidenhead Aquatics as Pearl gobies, Awaous grammepomus.
Price: £5.50