Medaka (killifish) is a species of killifish in the suborder Medaka, family Medaka. It is also known as the broad-tailed killifish and the big-eyed thief fish. For small upper freshwater fish, body length of about 20 to 26 millimeters, body shape lateral compression, dorsal straight, ventral margin slightly rounded, the head is moderately large, more flat, eyes,. The mouth is small. The lower jaw is slightly longer than the upper jaw. Head and body covered with rounded scales, 27-30 scales in longitudinal row. See below:

Mosquito-eating fish, Killifish, 1 species of the genus Mosquito-eating Fish, family Killifish. The body color is gold with greenish, the abdomen is obviously bulging, adults usually usually body length of 50 millimeters, weighing about 2 grams, large up to 80 millimeters, weighing up to 5 grams, teeth are small, the snout is pointed, the eyes are large, no lateral line, belongs to the oviparous fish. The dorsal fin has 7 to 9 soft bars; the anal fin has 9 to 10 soft bars. Males have long genital pores, while females have fan-shaped anal fins, and males are brightly colored. Males are slightly elongate; females have a rounded convex ventral margin. Head broad and short, flattened anteriorly. Snout short. Eyes large, interocular intervals broad and flat. Mouth small, superior, orifice transverse. Teeth minute. Head and body covered with rounded scales. No lateral line. In males, the third to fifth anal fins are extended and deformed into spermatophores. Caudal fin rounded. See the following figure: