Japanese Medaka ( Oryzae latipes )

Japanese Medaka (Oryzias latipes) is a fish of the family Ricefish bereasal from east asia. This fish has many names such as Japanese Ricefish, Medaka, Japanese killifish and Moonlight Medaka. Japanese medaka spread from Japan, Korea, China and Vietnam with the fast-flowing river habitat slowly. The report mentions that there are fish ever seen on the Nam Theun river, Mekong, Irrawaddy, Salween, Red River and Nanpangjiang. This fish is a popular fish in Japan 17an century.

At that time, the number of fish is very abundant in the market. Among other reasons they maintain the beauty of the color of the body and his endurance is remarkable. These fish are Amphidromous which means that they can move between fresh water and salt water several times during his life. In other words, they can be kept in freshwater and brackish water. This is evident from the habitat of fish that can be found in the sea and rivers. There are 22 known species of Oryzias and among them only ikanini that require refrigeration in maintenance due to habitat that is located in a subtropical climate. Fish that have the nickname of Geisha-girl is not listed in the IUCN Red List which indicates that the fish is not under threat in their natural habitat. This fish has a fairly small body size with a body length of about 4 cm. She was slender, elongated with a slightly curved back. This fish has a fairly large sparkling eyes. Colors varied body begins to brown and golden yellow in the wild, while in the aquarium breeders bred white, creamy yellow and orange.

Taxonomy

Kingdom     : Animalia
phylum        : chordates
Class           : Actinopterygii
order           : Beloniformes
Family         : Adrianichthyidae
genus          : Oryzias
species        : Oryzias latipes

 
Demi and market research purposes, this fish has been the subject of genetic modification experiments to obtain good quality as ornamental fish. One of them, the scientists insert fluorescent protein (a protein that can absorb color and will transmit back) from the jellyfish into the fish embryos. As a result, some fish have the ability to show the beautiful color (greenish, reddish, etc.) in the dark or low light. Randomized studies also showed medaka fish mutation. Mutations caused by genetic changes in the structure of DNA caused by external factors. In the mutated fish, look at the bones in the caudal fin (tail base) Diphycercal shaped, but generally these fish have bones Homocercal shaped caudal fin. Diphycercal cause fish tail shape resembles ancient fishes of the order Sarcopterygii (family Coelacath). Mutation results shown by the absence of scales and fins are elongated.

Sex differentiation in fish is not an easy task, but usually male fish has a more slender body. In addition, males also have a dorsal fin and anal wider. In Japan, the fish will begin to lay eggs in april to october. Treatment in aqurium allow fish to spawn when the water temperature 60 oF and the exposure time is also enough time per day due to lack of lighting will hinder the process of laying eggs. Ricefish family fish have an unusual reproductive process. The process of fertilization occurs externally, but these fish can apparently also perform internal fertilization. This ability is usually to exchange the reproductive form in a number of fish in extreme conditions unusual. Japanese medaka can dipijah in a tank with either leaf or similar plant mop. Spawning process can be initiated by placing a pair of fish or a small fish in the spawning tank. Fertilization process will begin when the male fish clung to the female abdomen. Female fish that already contain eggs will look fatter. Female fish eggs will not spread but it will take him a way to hang it on their genitals that are still open. Eggs are taken usually numbered between 10-20 grains. Actually, the female will produce an egg every day in consecutive days every week. If the egg is not fertilized, then fertilization occurs externally, and usually occurs in the morning is amazing. Eggs that had been taken a few hours after fertilization the female, will be attached to aquatic vegetation. Emotion female fish do it slowly to attach their eggs on the stems or leaves. Eggs are not hard to find on aquatic vegetation. Plants with floating leaves very suitable as a storage Eggs. The fish eggs are generally large and coarse. Fish eggs can be transferred to a hatching tank to collect these plants using fingers one by one. After the eggs will hatch 10-14 days depending on water temperature. Affect the water quality is very important in fish egg incubation period. Maintenance of water quality and cleanliness is very important to protect fish eggs from fungal attack. Newly hatched baby fish can be fed liquid or brine shrimp nauplii, red infusoria and newly hatched baby brine. 

Japanese medaka fish is a peacemaker and maintained in a group match. Special tank setup is not required for maintenance but water parameters must be maintained at a temperature of 18-24 ° C, pH 7-8 and 9-19 odGH hardness. The presence of aquatic plants make fish more comfortable and they like good aeration and water is constantly moving. Tankmate fish should be the size and not aggressive like the zebra danio, molly, platy and others. These fish tend to be omnivores to eat different types of foods, including dried and frozen foods. Types of live foods such as brine shrimpe, black worms and zooplankton liked very much. They are also good as a mosquito repellent and larvae, guard in groups for best results.