Dwarf gourami
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| Dwarf Gourami | ||||||||||||||
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| Colisa lalia (Hamilton, 1822) |
The dwarf gourami, Colisa lalia, is an attractive fish. It has an almost translucent blue color, with vertical red to dark orange stripes. In its native range, it is dried for food and kept as an aquaruim fish. It has become highly popular for aquaria.
Dwarf gouramis from Singapore may carry dwarf gourami iridovirus. Recent research has shown that 22% of Singapore Colisa lalia carry this virus.[1]
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[edit] Distribution and habitat
The dwarf gourami originally came from the Indian subcontinent; it originates from India, Pakistan, and Bangladesh. However, it has also been widely distributed outside of its native range.[2] This fish inhabits slow-moving streams, rivulets, and lakes with plenty of vegetation.
[edit] Appearance and anatomy
As its name implies, this is a small gourami: at maturity, it will reach an average size of 4 to 5 centimeters, though some individuals can grow as large as 8.8 centimeters.[2] Male dwarf gourami in the wild have diagonal stripes of alternating blue and red colors; females are a silvery color. They carry touch-sensitive cells on their thread-like pelvic fins.[3]
[edit] Reproduction
The male builds a floating bubble nest in which the eggs are laid. Unlike other bubble nest builders, males will incorporate bits of plants, twigs, and other debris, which holds the nest together better.[4]
Once the nest had been built the male will begin courting the female, usually in the afternoon or evening. He signals his intentions by swimming around the female with flared fins, attempting to draw her to the nest where he will continue his courting display. If the female accepts the male she will begin swimming in circles with the male beneath the bubblenest. When she is ready to spawn she touches the male on either the back or the tail with her mouth. Upon this signal the male will embrace the female, turning her first on her side and finally on her back. At this point the female will release approximately five dozen clear eggs, which are immediately fertilized by the male. Most of the eggs will float up into the bubblenest. Eggs that stray are collected by the male and placed in the nest. Once all the eggs are secured in the nest, the pair will spawn again. If more than one female is present in the breeding tank, the male may spawn with all of them. The spawning sessions will continue for two to four hours, and produce between 300 and 800 eggs. Dwarf gourami have a fecundity of about 600 eggs.[2] Upon completion, the male will place a fine layer of bubbles beneath the eggs, assuring that they remain in the bubblenest.
The male will protect the eggs and fry. In twelve to twenty-four hours the fry will hatch, and continue developing within the protection of the bubblenest. After three days they are sufficiently developed to be free swimming and leaving the nest. When the fry are 2-3 days old the male should also be removed or he may consume the young.
[edit] In the aquarium
[edit] Aquarium requirements
Most dwarf gouramis live for about four years but with proper care can live longer. Dwarf gouramis are peaceful fish that do well in most community aquaria. They require a tank that is at least 10 gallons. They are usually found swimming on the middle to top regions of the aquarium. This is not surprising since, like all gouramis, the dwarf gourami is a labyrinth fish. That is, dwarf gouramis can breathe oxygen from the air through their labyrinth organ (like the betta) if necessary. It is important, therefore that the surface of the water be exposed to fresh air. This is usually accomplished by using a hood that allows air ventilation. If you are using good air pumps, this is not always needed, since the air pumps will refresh the air above the water.
The aquarium should be heavily planted and have at least part of the surface covered with floating plants. A darker substrate will help show-off the gourami's colors, and peat filtration is recommended. Dwarf Gouramis should not be kept with large, aggressive fish, but are compatible with other small, peaceful fish as well as with fellow gouramis. Male siamese fighting fish may attack dwarf gouramis and should be avoided. The males of larger gouramis species may also bully dwarf gouramis.[3] Despite their shy, and docile nature they are aggressive towards fellow dwarf gourami. Each fish tends to establish a territory, and hiding places are a must. Loud noises often scare them, so the tank should be in a quiet area. Regular water changes are a must, as this gourami can be susceptible to disease.[3]
Dwarf gouramis are tolerant of fairly high temperature. This can be used to eliminate fish diseases such as Ich from the aquarium. Temperatures of 84 °F (29 °C) are easily tolerated.
[edit] Feeding
A varied diet is very important to the dwarf gourami, which is an omnivore that prefers both algae-based foods and meaty foods. An algae-based flake food, along with freeze-dried bloodworms, tubifex, and brine shrimp, will provide these fish with proper nutrition.
[edit] Breeding
Besides the difference in color, the sex can be determined by the dorsal fin. The male's dorsal fin is pointed, while the female's is rounded or curved. .[5] The water level should be reduced to 7-10cm (6-8 inches) during spawning, and the temperature should be approximately 28-30 °C (82 °F). Vegetation is essential, as males build their bubble nest using plant material, which it binds together with bubbles. Nests are very elaborate and sturdy, reaching several inches across and an inch deep. Limnophila aquatica, Riccia fluitans , Ceratopteris thalictroides, and Vesicularia dubyana, are good choices for the breeding tank. Peat fiber may also be offered as building material.
After spawning the female should be moved to a different tank. The male will now take sole responsibility for the eggs, aggressively defending the nest and surrounding territory. When first hatched, the tiny fry should be fed infusoria, and later, brine shrimp and finely ground flakes.[4] Freeze-dried tablets may also be fed to older fry.
[edit] Color variations
Breeders have created different color variations, varying degree of red/blue coloring.[3] The neon red variant show a solid patch of bright red color. On the other hand, the neon blue variant is almost entirely covered with an amazingly bright blue color.
 flame morph |
 neon red morph |
 neon blue morph |
 blue morph |
[edit] References
- ^ Clarke, Matt (2006-11-23). Aquarium trade may have spread gourami virus. Practical Fishkeeping magazine.
- ^ a b c "Colisa lalia". FishBase. Ed. Ranier Froese and Daniel Pauly. May 2007 version. N.p.: FishBase, 2007.
- ^ a b c d Sanford, Gina (1999). Aquarium Owner's Guide. New York: DK Publishing. ISBN 0-7894-4614-6.
- ^ a b Axelrod, Herbert R. (1996). Exotic Tropical Fishes. T.F.H. Publications.
- ^ title=Sex|last=Ristic|first=Mihajlo|publisher=Nolit|date=1973}}
- Colisa lalia (TSN 172626). Integrated Taxonomic Information System. Retrieved on 11 March 2006.
