Lake Toba is a large natural lake in North Sumatra, Indonesia, occupying the caldera of a supervolcano. The lake is located in the middle of the northern part of the island of Sumatra, with a surface elevation of about 900 metres (2,953 ft), the lake stretches from 2.88°N 98.52°E to 2.35°N 99.1°E. The lake is about 100 kilometres long, 30 kilometres (19 mi) wide, and up to 505 metres (1,657 ft) deep. It is the largest lake in Indonesia and the largest volcanic lake in the world. Toba Caldera is one of twenty geoparks in Indonesia, and was recognised in July 2020 as one of the UNESCO Global Geoparks.
Rasbora is a genus of fish in the family Cyprinidae. They are native to freshwater habitats in South and Southeast Asia, as well as southeast China. A single species, R. gerlachi, is only known from an old specimen that reputedly originated from Africa (Cameroon), but this locality is considered doubtful. They are small, up to 17 cm (6.7 in) long, although most species do not surpass 10 cm (4 in) and many have a dark horizontal stripe.
The spotted betta or Java fighting fish is a species of gourami endemic to Indonesia where it inhabits relatively cool, 22‒25 °C (72‒75 °F), highland streams of Java. In 1967, D. S. Johnson reported the species to be common in blackwaters of southern Malaya.
Betta is a large genus of small, active, often colorful, freshwater ray-finned fishes, in the gourami family (Osphronemidae). The best known Betta species is B. splendens, commonly known as the Siamese fighting fish and often kept as an aquarium pet.
The twospot rasbora is a species of ray-finned fish in the genus Rasbora native to south east asia. It is one of the members of the Sumatrana group.
The yellow rasbora is a species of ray-finned fish in the genus Rasbora from Southeast Asia. It is a primarily freshwater fish originally from Java island in Indonesia. It is known as the Wader pari fish in the Indonesian language. In addition, it was a protein source for the local community during the old days.
The copperstripe rasbora is a species of ray-finned fish in the genus Rasbora from Sumatra, Indonesia.
Rasbora reticulata is a species of ray-finned fish in the genus Rasbora from Sumatra and Nias Island in Indonesia.
Rasbora tobana is a species of ray-finned fish in the genus Rasbora from Sumatra, Indonesia. It is restricted to Lake Toba and some of the rivers than run into the lake.
Betta bellica. the slim betta or slender betta, is a species of betta native to eastern Sumatra in Indonesia and Peninsular Malaysia. It is an inhabitant of swamp forests and peat swamps. This species grows to a length of 10 cm (3.9 in). It can also be found in the aquarium trade.
Betta edithae is a species of gourami endemic to Indonesia where it occurs in Kalimantan, Sumatra and the Riau Archipelago. This species grows to a length of 8.2 cm (3.2 in), and can be found in the aquarium trade. The specific name honours the German aquarist Edith Korthaus (1923-1987), who co-discovered this species with her husband Walter Foersch. Walter is honoured in the specific name of another species they discovered, Betta foerschi.
Betta raja is a species of betta endemic to the island of Sumatra in Indonesia. It is an inhabitant of swamps in lowland forests. This species grows to a length of 6.4 centimetres (2.5 in) SL. It is used as bait by local fishermen and has also been found in the aquarium trade. Despite its scientific epithet "raja" meaning "Prince" or "king", this species is not identical to the aquarium breed - the King betta. The derivation of the King betta is not fully known and may or may not involve crossbreeding with B. raja.
Rasbora api is a species of cyprinid fish in the genus Rasbora. It inhabits the Kluet, Alas, Aek Batugarigis, Aek Sibundung, Batang Lumut, and Batang Toru rivers in Sumatra.
Betta cracens is a species of gourami endemic to the island of Sumatra in Indonesia. It is an inhabitant of freshwater swamp forest. This species grows to a length of 5.7 cm (2.2 in), typically inhabits blackwaters that have very soft and very acidic water and is a bubble nest brooder. The Latin term cracens means "slender" or "elegant" and is so named because of the fish's slender body. It was first described in 1996 by Heok Hui Tan and Peter K. L. Ng in The Raffles Bulletin of Zoology.
Betta pardalotos is a species of fish in the family Osphronemidae. It is native to Asia, where it occurs in the Musi River basin on the island of Sumatra in Indonesia. The species reaches 7.2 cm in standard length and is known to be a facultative air-breather. It feeds on insects and other small invertebrates such as zooplankton.
Betta fusca, commonly known as the dusky betta, is a species of gourami. It is a freshwater fish native to Asia, where it occurs on the island of Sumatra in Indonesia. The species reaches 8.2 cm in total length and is known to be a mouthbrooder and a facultative air-breather.
Betta renata is a species of gourami. It is native to Asia, where it occurs in blackwater rivers in the vicinity of peat swamp forests on the island of Sumatra in Indonesia. The environments in which the species occurs are characterized by acidic water with a pH of 4.1, as well as abundant plant debris and logs. The species reaches 8.5 cm in standard length and is known to be a facultative air-breather.
Betta andrei is a species of gourami in the family Osphronemidae. It is a black water fighting fish that is endemic to Singkep Island, Indonesia. It was described in 2023 by Heok Hui Tan, who named it after Andre Chandra, a fish collector and enthusiast who helped him during his fieldwork.
