Rasbora sarawakensis, from the Family Cyprinidae (The Sarawak Rasbora)
Although the name suggests that Rasbora sarawakensis is a freshwater fish from Sarawak, it has a wider range that includes West Kalimantan (Indonesia) and the Kalimantan Barat River Basins. This small fish is endemic to the island of Borneo and grows to a length of an average of two inches although larger specimens may have been reported.
In Sarawak, it can be found in shallow, highland streams. However, it is noted that water levels can rise dramatically during heavy rains, the streams experiencing pH and temperature variations during this time. Habitat parameter for pH is 5.50-7.50 as it also has been caught in streams in limestone areas. Favored water temperatures are an average of 23˚-27˚C as it tends to avoid warm bodies of water. Hardness is 2-11˚H, however, soft waters and a pH of 5.0 - 6.5 is considered most ideal. It also have been caught in waters with a strong Fe (iron) content, noted by red colored aggregates and soil matter in the stream beds and soils.
Rasbora sarawakensis is a schooling fish, but do not form large schools in the wild. Groups of three to ten specimens are the norm in Sarawak and generally, they favor mild currents in deeper waters and fairly strong, shallow currents. In fast currents, they love to huddle behind large stones or rocks on the stream bed. It is not really known of their exact dietary habits but they are opportunist feeders in the wild and have been observed to nibble on ripe wild fruits that sit in the water. Perhaps, they are not exactly eating the fruit but the maggots and organisms that feed on the rotting fruit.
Rasbora sarawakensis fries have been collected from the wild in slow moving waters with a slightly warmer temperature (28-30˚C) as these waters are usually sun exposed areas with vegetation (usually overhanging grasses and small bushes) leading to a boom in microscopic plankton that thrive on algae growth. The fries feed on these until they have grown and develop the proper body muscles to swim out into the water currents. The adults are generally spotted in sun-drenched and shaded areas of streams but are not exactly fussy with terrain types but generally prefer clean, clear, cold waters.
Domesticated specimens given the correct condition and foods are generally robust and long-lived about two to three years. They are excellent jumpers and tank covers are strongly recommended. A school of at least five specimens is recommended. The metallic bluish-black strip with a golden edge on the top of the strip and back that runs from the gill-plates to the base of the yellowish tail makes the fish a very desirable aquarium fish and colors typically are very strong in a medium school. Very healthy fish will have a very beautiful peppery scale pattern that stands out well. This is a very peaceful fish for a community tank but requires decent swimming space and will not do well in a small tank. Among themselves, they may chase each other but do not bother other tank mates. They generally occupy the middle and bottom strata of the tank and will happily at the surface to inspect anything that catches their fancy.
Easy to acclimatize to domestic conditions, these fishes will adjust decently fast to their new habitats. The tank should have gentle water currents to replicate their habitat. Healthy specimens usually will accept food within a few hours. During feeding time, they have a tendency to collect as much food as they can in their mouths while consuming it. Given the opportunity, they will gorge themselves until their bellies extend to a frightening bulge. A high protein diet with a low carbohydrate content brings out the colors of these fishes. They will readily accept dry and frozen fish feeds.
It is not known if this fish have been bred successfully. Most fishes for the aquarium industry are wild-caught and it would be good for breeders to work on this specie to meet demand and reduce loading on wild populations.
Although the name suggests that Rasbora sarawakensis is a freshwater fish from Sarawak, it has a wider range that includes West Kalimantan (Indonesia) and the Kalimantan Barat River Basins. This small fish is endemic to the island of Borneo and grows to a length of an average of two inches although larger specimens may have been reported.
In Sarawak, it can be found in shallow, highland streams. However, it is noted that water levels can rise dramatically during heavy rains, the streams experiencing pH and temperature variations during this time. Habitat parameter for pH is 5.50-7.50 as it also has been caught in streams in limestone areas. Favored water temperatures are an average of 23˚-27˚C as it tends to avoid warm bodies of water. Hardness is 2-11˚H, however, soft waters and a pH of 5.0 - 6.5 is considered most ideal. It also have been caught in waters with a strong Fe (iron) content, noted by red colored aggregates and soil matter in the stream beds and soils.
Rasbora sarawakensis is a schooling fish, but do not form large schools in the wild. Groups of three to ten specimens are the norm in Sarawak and generally, they favor mild currents in deeper waters and fairly strong, shallow currents. In fast currents, they love to huddle behind large stones or rocks on the stream bed. It is not really known of their exact dietary habits but they are opportunist feeders in the wild and have been observed to nibble on ripe wild fruits that sit in the water. Perhaps, they are not exactly eating the fruit but the maggots and organisms that feed on the rotting fruit.
Rasbora sarawakensis fries have been collected from the wild in slow moving waters with a slightly warmer temperature (28-30˚C) as these waters are usually sun exposed areas with vegetation (usually overhanging grasses and small bushes) leading to a boom in microscopic plankton that thrive on algae growth. The fries feed on these until they have grown and develop the proper body muscles to swim out into the water currents. The adults are generally spotted in sun-drenched and shaded areas of streams but are not exactly fussy with terrain types but generally prefer clean, clear, cold waters.
Domesticated specimens given the correct condition and foods are generally robust and long-lived about two to three years. They are excellent jumpers and tank covers are strongly recommended. A school of at least five specimens is recommended. The metallic bluish-black strip with a golden edge on the top of the strip and back that runs from the gill-plates to the base of the yellowish tail makes the fish a very desirable aquarium fish and colors typically are very strong in a medium school. Very healthy fish will have a very beautiful peppery scale pattern that stands out well. This is a very peaceful fish for a community tank but requires decent swimming space and will not do well in a small tank. Among themselves, they may chase each other but do not bother other tank mates. They generally occupy the middle and bottom strata of the tank and will happily at the surface to inspect anything that catches their fancy.
Easy to acclimatize to domestic conditions, these fishes will adjust decently fast to their new habitats. The tank should have gentle water currents to replicate their habitat. Healthy specimens usually will accept food within a few hours. During feeding time, they have a tendency to collect as much food as they can in their mouths while consuming it. Given the opportunity, they will gorge themselves until their bellies extend to a frightening bulge. A high protein diet with a low carbohydrate content brings out the colors of these fishes. They will readily accept dry and frozen fish feeds.
It is not known if this fish have been bred successfully. Most fishes for the aquarium industry are wild-caught and it would be good for breeders to work on this specie to meet demand and reduce loading on wild populations.
