Characteristics of the black medaka and how to keep them

The black killifish has long been found in Japanese rivers. In recent years, however, their numbers have been declining to the extent that they have been listed as an endangered species. In this article, we would like to explain in detail the characteristics of the black killifish and how to keep them.

What is Black killifish?

The black killifish is one of the oldest killifish species in Japan. It is the oldest killifish found in the natural world, and many of the killifish that were taken from rivers in the past are often black killifish.In recent years, however, their numbers have declined, and in 2003 they were listed as an endangered species in the Red Data Book published by the Ministry of the Environment. Therefore, if you find black killifish in the river, try to catch only a few. However, black killifish are sold at specialty stores. Black killifish sold at specialty stores can be purchased only from aquaculture or from natural habitats that are well controlled.

Origin of the black killifish

The black killifish is close to the native species of killifish and is the source of medaka such as the scarlet killifish, which is still very popular today.Black killifish have long been found in Japanese rivers and can be divided into two main types. One will be the "northern killifish.As for habitat, it is found on the Sea of Japan side of Honshu and in northern Japan, including the Tohoku and Hokuriku regions.The other will be the "southern killifish.As for habitats, they are found on the Pacific side of Honshu, as well as in southern and western Japan, including the Shikoku and Chugoku regions and Kyushu. Also, please note that southern killifish can be mistaken for the non-native species "kadayashi" in some regions.The northern and southern killifish are collectively known as "Japanese killifish.

Points to keep in mind when mixing swimmers

About Mixed Swimming,Some people often think that killifish can only be kept in the same species, but the real appeal of killifish is in combining them. If you are not particular about this, you can mix any kind of killifish with any other kind of killifish.However, it is best to be careful with killifish of different body types (e.g., Dharma killifish and Hirena killifish). If killifish of different body types are mixed with killifish of normal body type, problems such as inability to eat food may occur. However, there are people who mix killifish of different body types with those of normal body types, so there is no need to be concerned.However, each type of killifish, which is considered a high-end killifish, has its own distinctive appearance and shine, so it is recommended to keep them in a way that allows the enjoyment of each individual (type) rather than keeping them in many different species.

Points about spawning

The point about spawning was explained in the above section that keeping a variety of species is the best part of keeping killifish, and having various species swimming together when spawning will naturally produce killifish with the characteristics of various species. However, that is not always a good thing. For example, mixing red and white killifish can produce pink killifish, but not necessarily red or white killifish, or in the worst case, killifish with a color that is hard to describe. If you want red killifish, you should keep only red killifish because the probability of producing red killifish is much higher,I recommend that you think about what kind of killifish you want when spawning and what color and shape you want your killifish to be born, so that you will have less regret and confusion when raising them and find your own way to enjoy them.If it is just a hobby, I think you will enjoy it more if you stick to the methods that you enjoy, regardless of whether people complain about them. The following page explains the method of spawning and points to note, so please read it as well.

Points to keep in mind when keeping black killifish

Black killifish are very easy to keep, partly because they are close to the native species. They are inexpensive in many cases, but can be a bit expensive in some areas, but they are relatively inexpensive among killifish and are recommended for beginners.One thing to keep in mind when keeping black killifish is that black killifish have a more developed ability to adapt to their surroundings (protective coloration) than other species. For example, if the surrounding environment is bright, they lighten their body color and become almost transparent. Conversely, if the surrounding environment is dark, they darken their body color and hide in the shadows. In this way, black killifish adapt to their surroundings, so if the environment in which they are kept is easily lit, such as a glass case, they will not be very black, so care must be taken. If you want to appreciate the black color of the killifish, you should keep them in a bucket or a water lily pot and choose the darkest color possible for the bottom floor, but then it will be too dark and you will not be able to see the killifish. So please think about how much you can compromise. If you prefer to see black killifish a little better, you can try to make the color of the substrate a little brighter. If you keep the killifish in a glass case, it does not mean that they will die.