Japanese Medaka ( Oryzae latipes )

 

Japanese Medaka (Oryzias latipes) is a fish of the family Ricefish the 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 a slow-moving stream habitats. The report mentions that there are fish ever seen in the Nam Theun river, Mekong, Irrawaddy, Salween, Red River and Nanpangjiang. This fish is a popular ornamental fish 17an century in Japan.

At that time, the number of fish is very abundant in the market. The reason they maintain the beauty of the color of the body and the other body resistance incredible. 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 ocean and rivers. There are 22 known species of Oryzias and among them only fish that require cold temperatures to maintain because of 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 lustrous eyes. Body color varying from brown and golden yellow in the wild, while in the aquarium bred breeder white, creamy yellow and orange.

 
TAXONOMY

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Beloniformes
Family	Adrianichthyidae
genus	Oryzias
Species	Oryzias latipes

For the purposes of the research and market, this fish has been the subject of many experimental genetic modification to obtain good quality as ornamental fish. One of them, the scientists insert fluorescent protein (a protein that can absorb color and will spread it back) from a jellyfish into the fish embryos. As a result, some fish have the ability to display beautiful colors (green, red, etc.) in the dark or low light. Research has also shown the fish Medaka random mutation. Mutations caused by genetic changes in the structure of DNA caused by external factors. In the mutated fish, seen in the bone on the caudal fin (tail base) Diphycercal shaped, but generally fish have bones Homocercal shaped caudal fin. Diphycercal cause fish tail shape resembles ancient fishes of the order Sarcopterygii (family Coelacath). Another mutation results indicated the absence of scales and fins are elongated.

Japanese Medaka females and their eggsSex differentiation in fish is not something that is easy, but usually the male 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 until October. Treatment in aqurium also allow fish to spawn when the water temperature is 60 oF and the exposure time is also enough time per day due to lack of lighting would impede the process of laying eggs.  

Fish Ricefish family have an unusual reproductive process. The process of fertilization occurs externally, but these fish can apparently also perform internal fertilization. This ability to change shape usually reproductive 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 attaches a hold on 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 points. Actually, the female will produce an egg every day in consecutive days each week. If the egg is not fertilized, then fertilization occurs externally and usually occurs in the morning is amazing. Eggs have taken a few hours after fertilization females, will be placed on aquatic vegetation. Haru female fish do it gently to attach their eggs on the stems or leaves. The eggs are not hard to find on aquatic vegetation. Plants with floating leaves very suitable as a storage eggs. 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. Water quality is very important influence in the incubation period of the eggs of fish. Maintenance of water quality and hygiene is very important to protect fish eggs from fungal attack. Chicks newly hatched fish can be given liquid food or brine shrimp nauplii, red infusoria and newly hatched baby brine.

Japanese Medaka is a peacemaker and a suitable fish kept in groups. No setup is required for maintenance but the special tank 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 fishing 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 food like brine shrimpe, black worms and zooplankton loves. They are also good as a mosquito repellent and larvae, keep in groups for best results.