尾びれが非常に長く、中には体長の10倍にもなるものもある。
体色は鮮やかで美しく、色彩の違いによりいくつかの種に分けられる。
飼育には非常に手間がかかり、尾びれを傷つけないように大きな水槽が必要である。
特にこの《極光》は尾鰭が薄く、神経質な性質の為飼育が最も難しいと言われる。しかし、夜空に広がるオーロラのような美しさは人の心を惹きつけてやまない。
They have very long caudal fins, some of which can be 10 times the length of the body. Their body color is bright and beautiful, and they are divided into several species according to their coloration. Breeding is very labor intensive, requiring a large aquarium to prevent damage to the caudal fin.
The "Kyokko" in particular is said to be the most difficult to breed because of its thin caudal fin and nervous nature. However, its beauty, like the aurora borealis spreading across the night sky, is a magnet for people's hearts.