Order Beloniformes
Family Adrianichthyidae
Subfamily ( Oryziinae )
Genus Oryzias.
— Oryzias javanicus (Bleeker, 1854) – Javanese Ricefish. Synonym: Oryzias melastigmus, Aplocheilus mcclellandi, javanicus. (Engl. Javanese Ricefish). Code: JVC. India, Myanmar, Malaysia, Indonesia, Sri Lanka, Sumatra, Java, Borneo, Bali, freshwater or slightly brackish coastal waters, ditches and canals, mangrove swamps. 4 cm. Body moderately slender, compressed laterally. Eyes large. Body transparent, gray-green with a bluish and reddish sheen, upper part olive-brown with dark streaks and blue sparkles, lateral line dark.
Dorsal and anal fins of males are broad with a blue margin and rays extending beyond the fin edge. A black spot is present at the base of the dorsal fin. Tail fin truncated, with yellowish stripes along the edges. Male is more slender, dorsal fins higher, anal fin fringed. Internal organs are clearly visible. Fry are ordinary gray.
Peaceful schooling, active and timid fish, staying in the upper water layer. Best kept in a species aquarium with patches of live plants. They are more heat-loving and should be kept at a temperature of about 25°C. Not demanding on water chemical composition; salt can be added at 1 g per liter. Fish are omnivorous, eating live and substitute foods in aquariums. Sexual maturity at 10 months. Fertilization is external. Females attach fertilized eggs to their belly. Eggs fall off as the female brushes her belly against plants. Lifespan in captivity is 2-2.5 years. pH 6.5-8.0; T 24-29°C.
— Oryzias latipes (Temminck & Schlegel, 1846) — Japanese Medaka. Synonym: Poecilia latipes. (Engl. Japanese Rice Fish, Medaka, Moonlight Medaka). Inhabit irrigation systems and rice fields in China, Korea, Vietnam, Uzbekistan, Kazakhstan, southern Japan, and Taiwan. Fish reach 3-4 cm in length. Body semi-transparent, elongated with a slightly arched back. Eyes large.
Wild cream-colored versions of this fish are not particularly attractive, but over time breeders have developed new color forms. They have large, beautiful luminescent eyes. The most famous versions are — Golden medaka “Gold Medaka” and — Moonlight medaka “Moonlight Medaka”, as well as a red breeding form.
Coloration is gray with a yellowish or bluish tint, shimmering with greenish or bluish tones. A narrow dark longitudinal stripe runs along the side. Males are smaller and more slender than females. Fins are transparent with an orange margin. Pectoral fins are positioned relatively high. In males, pelvic fins are dark, almost black with a blue tint during the spawning period.
Adult males have a small dorsal fin set far back, pointed, with elongated filamentous rays. Individual rays of the anal fin are elongated. In females, the dorsal fin is rounded; in some females, pectoral fin rays reach almost to the anal fin. Iris of the eye is blue. O. latipes has a truncated, rather than crescent-shaped or notched caudal fin, which distinguishes it from relatives.
Scientists added jellyfish protein to their DNA, producing yellow-green fluorescent fish whose internal organs and skin glow in the dark, named “TK-1”. They also managed to obtain fish with fluorescent blue pigmentation (“TK-3”) and pink pigmentation (“TK-4”). They are now available in several colors including yellow, green, red, and purple, and truly glow in the dark.
Peaceful, schooling, and active fish; tankmates should be of similar size and non-aggressive. They swim in the upper layers of water. Best kept in a school in a species aquarium with thickets of live plants, including floating ones, with a tightly covered top. Cannot be kept with large aggressive fish. Tolerates water salinity well. Feed with zooplankton, flakes, pellets, live and frozen bloodworms, daphnia. They feed from the water surface.
Mature at 6-8 months. Spawning is in pairs or groups with a predominance of females. Spawning usually occurs at dawn; internal fertilization is characteristic, occurring a few hours before egg deposition. A cluster of eggs remains attached to the female by a thin thread until she brushes against a plant, to which the entire clutch adheres. Eggs hanging under the female’s belly are usually clearly visible and may remain there for about 2 days. Fish spawn regularly, releasing one cluster of eggs weekly, but parents may eat them if given the opportunity. Lifespan in captivity is up to 3 years. dH 5-15°; pH 6.5-7.8; T 18-24°C.
— Oryzias sarasinorum [Popta, 1905] — Sarasin’s Buntingi. Synonym: Haplochilus, Xenopoecilus sarasinorum. (Engl. Sarasin’s Buntingi, Sarasins minnow). Indonesia, Sulawesi, Lake Lindu. 6 cm. Scales small. Body of a delicate silvery-bluish color. A wide silvery lateral stripe extends from the gills to the caudal peduncle. Fins unpatterned, matching body tone. Males have elongated, filamentous rays in the dorsal and anal fins.
In females, pelvic fins are elongated, and the abdominal cavity between pectoral and anal fins has a deeply concave area used to transport an egg packet of 8-12 eggs, held by the elongated pelvic fins. Unlike most Oryzias species, the female carries them until they hatch, usually 14-20 days.
Peaceful, but given its rarity, best kept in a large group in a species aquarium. This species has no special requirements for aquarium setup; it should be spacious with dense vegetation around the perimeter where fry can hide, along with driftwood and stones. Diet consists of small live and frozen foods such as daphnia, Artemia, chopped bloodworms, along with good-quality, suitably sized flakes and pellets. pH 6.8-8.0; T 23-28°C.
— Oryzias woworae [Parenti & Hadiaty, 2010] — Daisy’s Ricefish. (Engl. Daisy’s Ricefish). Southeastern Sulawesi, Muna Island, in freshwater forest streams. 3-4 cm. Body blue with a bright sheen. Eyes intense blue. Gill covers and body near pectoral fin are silvery.
Abdominal surface of the front part of the head and body, pelvic fins, base of pectoral and dorsal fins, rear part of anal fin, edges of the tail base, and caudal fin are bright red. Caudal fin is arc-shaped. Adult males are more slender, much more intensely colored, with elongated dorsal and anal fins compared to females.
Suitable for a nano aquarium. Keep in small groups in an aquarium with thickets of fine-leaved plants and floating vegetation with long roots. Females are capable of spawning 10-20 eggs every few days, usually early in the morning. Males darken in color during spawning and defend a small, temporary territory against each other while trying to entice females.
A cluster of eggs remains attached to the female by a thin thread until she brushes against a plant, where the entire clutch or individual eggs are glued. Omnivorous; fed live and frozen foods, including dry flakes. Lifespan is 3 years. pH 6.0-7.0; dH up to 15°; T 23-28°C.
Identification: Daisy’s Ricefish — Oryzias woworae.
Description of the family Gymnotidae, Gymnotus carapo.
Oryzias celebensis, Oryzias matanensis. 
