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.

 

BETTA BROWNORUM

Betta brownorum, a wild dwarf fighting fish was once found in numbers in the swamplands of Sarawak. This is easily the most beautiful member of the Coccina family. Unfortunately, rapid development take over many of their habitats and it is not easy to find these beautiful gems these days. They still exist in very small pockets of swamplands in highly tannin waters with pH sometimes as low as 3.5. These are wild-caught fishes last January 2010.

Breeding this fishes requires extremely clean water with a pH of 3.5-6.6. My experiences have shown that they will breed in shallow water with a depth of 3 inches up to 7 inches with a lot of Java Moss with the tank receiving indirect sunlight. The down side is they produce extremely small clutches of eggs (9-17 eggs) in a single breeding.

Microworms

MICROWORMS CULTURE

Microworms thought to be Panagrellus redivivus are part of an important live food inventory for fish breeders as it is an important food source for raising tiny fish fries such as wild betta(s). Much have been written on this subject and on our initial trials, found that many of them are not suitable for us as they were written by and for the hobbyist with a small number of tanks.

With more than one hundred and seventy tanks to upkeep, we eventually come to a conclusion that a consistent principle, K.I.S.S. (Keep It Straight and Simple) is good practice as it eliminates waste, unnecessary work and save us time and effort.

After several trials, I use this simple in-house recipe in our breeding facility because the ingredients are available almost any time, anywhere and inexpensive. These are found in most bakery supply shops, supermarkets and the grocery shop.

They are;

1. 200g ordinary bread (high-protein) or plain flour; bread flour give a slight better result in yields. Avoid refined or expired flours.
2. Baker’s yeast or instant yeast (Standard 11g packet).
3. And 100g boiling water.

For your equipment, you may need the following;

Note: All food-contact equipment used for micro-worm production should not be used for human and other pet (cat, dog, bird etc) food production. 

1. A weighing machine (We use a Tanita KD160 digital scale with a tare function. This machine is affordable and importantly, reliable. Newer models have replaced this range)
2. Four clear, clean plastic containers with tight lids. Capacity is 400ml with a wall height of 60mm. A wall too shallow do not contain the nematodes properly when they crawl up the sides
3. New dish-washer sponges
4. A heat-resistant soup dish or bowl
5. A metal dinner spoon
6. Pastry brush
7. Dish of clean water
8. A starter culture
9. A water spray bottle, set to ‘fine mist’

The thumb of measurement is 1:½ meaning for every part of flour, half part of water In Weight, NOT Volume applies. With this ratio, one can use it regardless of either metric or imperial measurement. Example; if you use 160g of flour, add 80g of water. If you use one pound of flour, you add eight ounces of water.

Firstly, make a hole in the middle of the container’s lid. Cut the sponge to a cube size and make side slits to allow the cubes to fit snugly into the hole(s) and they will not slip out. Set aside.

Place the dish or bowl on the weighing machine and press the tare button. It will calibrate the weighting machine by bring the scale reading back to Zero. Weigh out the flour into the dish or bowl. When you are done, continue by pressing the tare button on the weighing machine again to reset it. Make a well in the center of the flour; pour boiling water straight from the stove into the well until it reads 100g. The hot water basically cooks the flour, and breaks down the starches.

Use the metal spoon to mash in the flour to make a stiff dough. Do this while the dough is hot. Once the dough cools down sufficient to be handled, knead the dough by hand until the dough is smooth. It should not stick to the sides of the bowl or your hands or fingers. If it is too sticky, add a little flour. If it is too dry, add a little water until you obtain the right consistency. That’s why I love the digital machine. It takes the guesswork out and delivers consistent results.

Divide the dough into 4 equal parts and form them into ball-shape dough. Flatten the dough into a thin disc to fit neatly into the base of the containers. At this stage, before I place the dough into the container, I will coat them with a wet brush to make the surface moist on both sides. Once the dough is inside the containers, sprinkle the yeast very lightly on the surface. Imagine that you are shaking salt on that favorite ribeye steak you are going to chow on.

Before you introduce your micro-worm culture, ensure that the dough is at 30˚C or room temperature. A lump the size of half a green pea is sufficient. Cover securely with the lid and place in a well-ventilated location that is not exposed to the sun. Make sure the location is free of ants and mites. You also might want to consider the location as it does generate a faint aroma which may be a turn-off to others.

By the second day, you should be able to harvest your first microworms. The surface of the dough should be dry by now. Apply a fine mist of water into the container after you have harvested the worms. The mist should only moisten the surface, not flood it. Several hours, you will be able to harvest another crop of micro-worms, and again, and again for up to six days. The image below shows a culture on its sixth day.

Some writers have expressed that after a week, you can add new food and yeast into the cultures and they can be recycled for a few more times. We find that microworm production is greatly reduced after eight days when the dough breaks down, gets polluted with waste products and have a funky smell. It's really more logical to harvest them all out and start a new batch. Quality matters and your cultures will not crash.