Betta Krataios

Betta krataios (commonly known as the Kapuas Betta) is a small, robust labyrinth fish native to the island of Borneo. Its name is derived from the Greek word krataios, meaning "strong" or "sturdy," which refers to its relatively thick body build compared to other members of its group.

​🐟 Physical Characteristics

​Size: A small species, typically reaching a standard length of 4.5 cm (approximately 1.8 inches).

​Coloration: The body is generally yellowish-brown. One of its most identifying features is the iridescent turquoise scales on the opercle (gill cover) when the fish is alive.

​Fins: It possesses a rounded caudal (tail) fin. In males, the anal and tail fins may display a brilliant iridescent band, and the fins are generally more extended than those of females.

​Distinction: It is often compared to Betta dimidiata but can be distinguished by its rounded tail (whereas B. dimidiata has a spade-shaped or lanceolate tail) and its yellowish body and fins (as opposed to reddish).

​🌿 Habitat and Ecology

​Origin: It is endemic to the lower Kapuas River basin in West Kalimantan, Indonesia.

​Natural Environment: They inhabit shaded forest swamp streams and pools, which can sometimes be only a few centimeters deep. These waters are typically slow-moving or still, soft, and slightly acidic, often filled with dense vegetation and leaf litter.

​Breeding: Betta krataios is a paternal mouthbrooder. After spawning, the male carries the fertilized eggs in his mouth for a period of 7 to 12 days (averaging about 9 days) until they hatch and are released as free-swimming fry.

​🧪 Aquarium Parameters

​For those keeping this species in captivity, the following conditions are generally recommended:

​Tank Size: Minimum of 40 liters (approx. 10 gallons) for a pair.

​Temperature: 23°C to 27°C (73°F to 81°F).

​Water Chemistry: Prefers soft, acidic water (pH 5.0–7.0) but is noted for being relatively tolerant of varying water chemistry if the water is kept clean and well-filtered.

​Diet: They are naturally insectivorous, preying on small invertebrates. In an aquarium, they thrive on a varied diet of live or frozen foods like Daphnia, bloodworms, and brine shrimp.

​⚠️ Conservation Status

​The IUCN Red List currently categorizes Betta krataios as Data Deficient (DD). While specific population trends are not fully documented, like many wild Bettas in Southeast Asia, they face potential threats from habitat loss due to land conversion for agriculture and plantations.