Parosphromenus filamentosus

Parosphromenus filamentosus is a licorice gourami of about 4 cm that lives in the peat swamps of South Kalimantan. A long filament extends from the middle of the males' spear-shaped caudal fin; this feature easily sets it apart from the other members of the genus. During courtship the males' dorsal and anal fins color up with red and bright blue-white bands. The male guards the eggs in the small bubble nest he builds on the ceiling of a cave.

• At least 20 liters for a pair; a species tank is best.
• 24–27°C, pH 4–6, GH 0–4; reverse osmosis water or rainwater.
• A thick layer of dried leaves, roots, small caves and dim light.
• Almost still water; small water changes with matching values.

A carnivore that feeds on tiny organisms and often refuses dry food. Live brine shrimp nauplii, cyclops, microworms and grindal worms should be the staple; it may accept small frozen foods over time.

Very calm and timid; it spends most of its time among leaves and caves, near the bottom. It goes hungry next to fast tankmates.

Good companions: only its own species; in a large species tank, very small and calm peat-water fish such as Boraras.

Avoid: fast schooling fish, gouramis and bettas, species that need hard water, other Parosphromenus species (they can hybridize).