Was ist ein Medaka?
Ein Medaka ist ein Fisch der Familie Adrianichthyidae und oryzias Gattung, die normalerweise als Reisfisch bezeichnet wird. Es wird manchmal als japanische Killifish bezeichnet. In addition to Japan, it is found in most of Asia, including Korea, China, and Vietnam, usually in ponds, marshes, and rice paddies.
The medaka is a very small fish, usually reaching about 1.6 inches (4 cm) in length. Sein Körper ist sehr schlank und länglich, mit einem gewölbten Rücken. Its very small size does not make the medaka a popular fish for fishermen, but its bright coloration and appearance has long made it a favorite of aquarium enthusiasts. In der Natur ist der Fisch normalerweise braun oder gelblich Gold. Captive breeding has increased their color range, with white, yellow, or pure orange variations not uncommon.
As aquarium fish go, the medaka is a fairly hardy fish that can survive in a wide range of water conditions. Die Wassertemperaturen können zwischen 65 und 75 Grad Fahrenheit (18 bis 24 Celsius) variieren., and pH levels can range from 7 to 8. As long as it is mixed with non-aggressive fish of a similar size, it makes a very good fish for community tanks.
Die Pflege des Fisches ist ebenfalls einfach. The medaka will eat a variety of foods, from flake and freeze-dried foods to a wide range of frozen foods. Like many smaller fish, it prefers to have plenty of cover in the tank to hide when stressed. It also requires some degree of water movement, which can be provided by an air stone or filter.
The medaka is also a popular fish for researchers thanks to its hardiness and relatively quick breeding cycle. Medaka have been extensively used in environmental research. Tests involving carcinogenesis and related fields of study have been conducted on the fish in the past. Genetic manipulations on the fish have created captive-only variants of the fish, including a type that glows florescent green.
The use of the Japanese killifish as a research tool has even extended to outer space. 1994 wurden vier Medaka an Bord der USS Columbia Space Shuttle für eine Vielzahl von Tests aufgenommen, da sie die einzigen Fischarten waren, von denen bekannt war, dass sie der Mikrogravitität standhalten. Not only did the fish thrive in the shuttle, but they bred, becoming the first vertebrates to produce offspring in space. The medaka kept aboard the Columbia laid 43 eggs, some of which hatched while still in space. All the fish that hatched both in space and back on Earth exhibited no noticeable side effects from their travels.