Order Atheriniformes
Family Melanotaeniidae
Continued…
Genus Melanotaenia.
— Batanta Rainbowfish — Melanotaenia batanta [Allen & Renyaan, 1998]. New Guinea, Batanta Island. 8-10 cm. Upper half of the body with neon blue, except for the brown scale edges, lower half of the body whitish-silver with a dark gray triangular spot above the pelvic fins. Narrow orange stripes run between each row of scales on the upper two-thirds of the flanks. Dark spot immediately behind the eyes on the upper part of the gill cover.
Fins mostly colorless, except for the dorsal, anal, and caudal fins, which often have a bluish tint. Clean water with frequent water changes, slight current. There is a slight difference between females and males, mainly in size, the female being smaller. Schooling fish. pH 7-8; dH 9-12°; T 20-24°C.
— Boeseman’s Rainbowfish — Melanotaenia boesemani [Allen & Cross, 1980]. Inhabit rivers and lakes of Irian Jaya province, in Lake Ayamaru, Lake Aitinjo and rivers flowing into them (New Guinea). Male 10, female 8 cm. Body oval-shaped, high, slightly elongated and laterally compressed. Caudal fin forked. Dorsal fin consists of two parts: the first is short (pointed in males, rounded in females); the second part, located closer to the caudal fin, as well as the anal fin, is long. Luxuriously colored fish. The front half of adult fish is colored differently than the rear half.
The front part of the males’ body is colored in a brilliant grey-blue, sometimes darker, the rear part (including fins) in a bright yellowish-orange. Between these two areas, there are alternating narrow light and dark vertical sea-blue stripes running from the back, colored in the same shade, to the belly. The first stripe begins at the level of the pectoral fins, the last runs in the middle of the body, and the middle one is equidistant from the outer ones. A greenish shiny stripe is visible along the body, closer to the back.
Narrow, elongated head and pectoral region of the body are dark green, becoming almost black during spawning. A brilliant silver spot surrounded by bluish sparkles is on the gill cover. Bright silver, yellow, and orange shiny scales are randomly scattered across the body. When excited, the front part of the male’s body turns bluish-purple, the rear part is colored reddish-orange. Dorsal fin is orange with a greenish margin. Pelvic and anal fins are bluish. Males are more brightly colored, with a predominance of yellow and orange tones. Full coloration appears at 11-13 months.
The female is smaller, has a less high back, and more rounded fin tips. Females are silver in the front, yellow-greenish towards the tail, have wide dark horizontal lateral stripes, and narrow yellow, red, or orange longitudinal stripes between the scale rows that become brighter or lighter depending on mood. Geographical color variations: — Melanotaenia boesemani “Ajamaru”; — Melanotaenia boesemani “Lake Aitinjo”; — Melanotaenia boesemani “Rote Ausleseform”;
Peaceful, schooling, active, free-swimming fish. A small school of fish can be kept in a covered community aquarium with dense plant thickets, best planted along the side and back walls, including fine-leaved plants creating shaded areas, but also leaving plenty of free swimming space. Can be kept with various fish species. They stay in the middle water layer. Prone to jumping out. Sensitive to low oxygen levels; aeration and weekly water changes are necessary.
Fish are very heat-loving, preferring temperatures of 27-30°C, although they can withstand a drop to 24-25°C without visible harm. pH value does not matter much to them. Fish easily tolerate both slightly acidic (pH 6.4) and alkaline (about pH 9.2) water. They can be fed live foods (cyclops, daphnia, bloodworms, tubifex, shrimp), vegetable, and dry foods rich in vitamins and microelements. Reach sexual maturity at 8-10 months of age. Breeding is not difficult, although coloration brightness fades from generation to generation. pH 6.4-7.8; dH 10-20°; T 25-29°C.
Identification: Boeseman’s Rainbowfish — Melanotaenia boesemani.
— Blue Rainbowfish — Melanotaenia caerulea [Allen, 1996]. New Guinea. 6-8 cm. Bright iridescent blue on the flanks and rear, becoming whitish or pink towards the belly. There is a faint dark blue stripe on the posterior half of the body, one scale wide. Between each row of scales on the blue part of the body, there is a narrow pinkish-orange stripe. Short brown stripe from the eye to the area slightly above the pectoral fin. Fins bluish to colorless. In males, the front edge of the first dorsal fin and the outer part of the second dorsal fin, as well as the anal fins, are sometimes reddish or blackish. Pelvic fins mostly grey to reddish, pectoral fins translucent.
Males are larger, bigger, and higher-bodied than females, more brightly colored, and have sharper ends of the dorsal and anal fins. Females have a lower body and rounded fin tips. It is advisable to keep them in a school of at least 4-5 individuals. Clean water with frequent changes, slight current. Eats any types of aquarium foods. T 20-27°C; pH 7.2-8.0; dH up to 16°.
— Waigeo Rainbowfish — Melanotaenia catherinae [de Beaufort, 1910]. Synonym: Rhombatractus catherinae. Inhabit the Raja Ampat island group, east of New Guinea. 7-10 cm. Body bluish to purplish brown on the flanks with a white belly. Median broad lateral stripe. Dorsal, anal, and caudal fins with a reddish tint.
Males are larger, bigger, and higher-bodied than females, more brightly colored, and have sharper ends of the dorsal and anal fins. Females have a lower body and rounded fin tips. Can be placed in a species aquarium or combined with other peaceful fish species of approximately the same size. Very tolerant of water parameters. Feed with foods that include live foods. pH 6.0-8.5; T 22-28°C.
Melanotaenia duboulayi, goldiei, gracilis, fredericki.
Melanotaenia affinis, angfa, arfakensis, australis. 
