Taxonomy & naming
Apistogramma sp. "D39" is an undescribed form known by a D number from the German magazine DATZ's catalogue of undescribed Apistogramma. A D number is a trade identifier only: it carries no authority, year or type specimen. The form is undescribed, and its identity and range are not documented in the sources behind the atlas.
Morphology
Wet Spot lists an adult size of about 2 in for males and 1.5 in for females. No colour description for this form is recorded in the atlas's sources.
Habitat
Not documented in the atlas's sources. Wet Spot gives the range only as South America. Genus-level: Apistogramma live in the Amazon, Orinoco and neighbouring basins, mostly in small streams over sand and leaf litter.
Feeding
Wet Spot says it is carnivorous and takes dried sinking pellets, flakes and frozen foods, with wild fish slower to accept dry food.
Mating
Not documented for this form. Genus-level: Apistogramma males hold a territory and court several females, each with her own cave.
Breeding
Not documented for this form. Genus-level: Apistogramma are cave spawners, and the female guards the eggs and fry. Wet Spot says to provide a small cave for spawning.
In the aquarium
Wet Spot recommends keeping it as a pair, in at least 15 gallons (about 15 US gal), with a sand bottom, plenty of cover and leaf litter. It describes the fish as semi-aggressive and shy, and suggests small South American schooling tankmates such as tetras or dwarf pencilfish. Its listed range is pH 4.5-7 and 71-82 °F. These are the seller's figures.
Conservation
An undescribed form has no IUCN category, and none is claimed here. Population and range data for it are not documented in the atlas's sources.