Rasbora kolachlorma

 Rasbora kolachlorma (Bleeker, 1851) from the Family Cyprinidae (The Clown Rasbora)


The Rasbora kolachlorma’s any closest resemblance to a clown are the two or three big dark green spots that flank both sides of the fish. It is also known as the Iridescent Rasbora. It has a rich, brown color that is overlaid with scales that have beautiful iridescent colors which is very evident when taken out from the water. A greenish fairy-dust pattern can be seen decorating the top of the fish from head to base of the tail. Fins are maroon-ish brown and do not have any markings. Found in peat swamp basins, it has a wide range in Borneo and Indonesia (Sumatra) and inhabits a wide range of habitats which includes shallow streams and peat swamp forests.

Their favorite habitats are submerged areas with thick vegetation, tree-roots, overgrown grasses and knee-deep waters under shade. They have a stream-lined body which enables them to traverse in fast currents especially during heavy rains but they prefer quieter bodies of water. This is a relative large, elegant Rasbora attaining a length of 11cm, as observed in the author’s specimens.

This fresh water fish’s habit parameters are usually clean, tannic, soft (2-5˚H) waters with a pH of 4.0-6.8 with a gentle water current. Water temperatures can vary from area to area but generally in the jungle and peat swamp fed streams, temperatures range from 25˚ -28˚C. Occasionally, they can also be found in stagnant bodies of waters, which usually is the result of a heavy rain overflow which traps them temporary. When the water levels rise with the next rains, they usually slip out of the stagnant pool to new hunting grounds. In the wild, they form small, loose schools with an average of three to five fishes.

Breeding is observed during the rainy season when the water levels rises and floods the jungle floors, sometimes for several days. Mature fishes gather in larger schools sometimes as many as thirty fishes and make migratory trips into the flooded jungle to breed. Favorite breeding platforms are peaty, grass over-grown areas with thick jungle canopies. Low light levels due to the jungle’s thick canopies are commonly observed.

Hatched fries are usually found in these flooded jungle floors in very gentle currents but fish count is usually about two to three fishes per square meter. As the waters slow ebb, some fries will follow the currents out and a few will be trapped in pools until the next rains come. The flooded jungle floor is rich in suspended microscopic food such as daphnia and aquatic larvae, and these form part of the foods for the fish and fries.

Juvenile fishes are observed to be competitive as they frequently chased and push weaker siblings away to dominate food resources and territories. This behavior is also observed in wild-caught adult specimens.

Scraping behavior is usually limited to their own specie. Otherwise, this is a very peaceful, benthopelagic fish that will fit a large community tank.

Wild adult fishes are observed to be surface feeders, preying on insects on the water such as water skaters and floating foods. However, domesticated specimens will readily adapt to frozen, dry foods with a high protein matter and low carbohydrate content. Wingless fruit flies are an excellent source of protein for them. Dry foods should be of the floating type. Rasbora kalochlorma often exhibit the ‘Squirrel Syndrome” as I called it. They will aggressively collect as much food as they can in their mouth or cheeks while consuming it. Hence in a community tank, it is necessary to closely observe that the rest of the occupants will have sufficient food to eat.

Properly cared for specimens are generally long-lived with an average life-span of three years. Rasbora kaloclorma is an excellent jumper with the ability to even jump out when they are netted so a tightly covered tank is recommended. Adult specimens are often observed as solitary fishes in the aquarium but will readily regroup as a school of fishes during feeding or mating times.

This is an excellent fish for the community bio-type tank. No commercial breeding has been observed for this fish and most of the Rasbora kalochlroma for the aquarium trade are wild-caught. Again with encroaching development into their habitats, this would be a good fish for breeders to include in their list.

Rasbora sarawakensis

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.