Order Cyprinodontiformes
Superfamily Egg-laying toothcarps ( Cyprinodontoidae )
Family Aplocheilidae
Genus Aplocheilus, Asian pikes – Aplocheilus. Apl.
Aplocheilus are distributed in India and Sri Lanka, and Pachypanchax on Madagascar and parts of the African continent closest to Madagascar. Fishes of this genus are characterized by an elongated body with a wide back, forming a single plane with the head that continues to the beginning of the dorsal fin and then transitions into a narrower caudal peduncle. The dorsal fin is small and located quite far behind the middle of the back. The high and long anal fin is also shifted backward. Together with the caudal peduncle, they form a single wide plane necessary for more effective propulsion when jumping for insects, which the fishes feed on in nature. The very wide mouth serves the same purpose. Due to the flat back, the fish can lurk near the water surface, which facilitates hunting.
— Aplocheilus blockii [Arnold, 1911] — Green Panchax, Block’s Aplocheilus, Madras pikes. Code: BLO. (Eng- Green Panchax). Inhabit the southern part of India and Sri Lanka. 4 cm. It is the smallest of the group. The body is yellow-green with small yellow spots, the belly is green-blue. Five rows of iridescent shiny blue, green, and red/pink spots stretch along the entire length of the flanks. The scales feature shiny and brassy-yellow spots, and in some populations, red spots. The coloration of males is brighter and the dorsal fin is slightly expanded. The male is yellow-green to olive-green, belly is green-blue. There is a bright green spot on each gill cover.
The anal fin is pale orange with red and blue spots, elongated and in some cases can reach almost to the caudal fin. The dorsal and anal fins are pointed and have a light orange edge. The dorsal fin is large, oval-shaped. Longitudinal rows of spots run along the caudal fin. Unpaired fins are lemon-yellow with red to brown spots and streaks. Pectoral fins are colorless, pelvic fins are orange. The female is paler, lacks red speckles, has a dark longitudinal stripe and several transverse stripes along the body, which are especially clear on the caudal peduncle; her caudal fin is round. There is a subspecies — A. blockii parvus (Code: PAR).
They look very nice in a small species aquarium with additional side lighting. The aquarium must be well covered from above, otherwise the fishes will find a sufficient gap and may jump out. Thickets reaching almost to the water surface are necessary. Fishes are peaceful, can be kept in a general aquarium where they stay in the upper water layer. It is advisable to keep them in a school of 6-10 specimens, with a larger number of females than males. Fishes do not like strong water movement. Very soft or very acidic water should be avoided. Easily bred in captivity. It is best to breed them in the same aquarium where they are kept; they spawn on leaves and roots of floating plants. Fry have dark longitudinal stripes that disappear as they grow. Hardness 4-12°, pH 6.5-7.0, temperature 22-24°C (can reach 32°C in nature).
— Aplocheilus dayi [Steindachner, 1892] — Day’s Green Aplocheilus, Day’s Light-eye, Ceylon Killifish. Code: DAY. Synonym: Aplocheilus johnklaasi. (Eng- Ceylon Killifish). Southern India, Sri Lanka, small swampy freshwater and brackish bodies of water. Grows up to 9 cm. The dorsal fin is shifted far back. Beige with greenish scales and 2-4 dark spots on the body. Tail with a coffee-green border on the lower lobe, other fins with dark streaks and spots. Fins of males have metallic green-blue sparkles. Dorsal and anal fins in males are pointed. The male is brighter and larger than the female. Subspecies: — A. dayi werneri from the southern part of Sri Lanka, up to 7 cm. Differs in size and coloration elements.
Compatible with medium-sized fishes. Lighting should not be bright, as green aplocheilists prefer to stay in the shade. The aquarium should have thickets of plants, including floating ones, creating additional shade, tightly covered with a lid on top. A schooling fish that feels good in schools of 6 or more individuals. 1-2 females are needed per 1 male. Occupies the upper water layer. Can be kept with peaceful fishes of the same size. Cannot be kept with large predatory fishes. In nature, it preys on small insects and their larvae, as well as fish fry. In captivity, it readily accepts any live, frozen, and dry foods. Sexual maturity at a size of 3-4.5 cm. Hangs its eggs on plants, usually near the tops. Hardness 6-8°, pH 6.6-6.8, temperature 24-30°C.
— Aplocheilus lineatus [Valenciennes, 1846] — Striped Aplocheilus, Striped Light-eye, Golden Wander Panchax. Code: LIN. Synonyms: Aplocheilus rubrostigmus, vittatus; Haplochilus rubropictus, lineolatus, lineatum; Panchax lineatum. (Eng- Gold Panchax, Golden Wander Panchax, Green Panchax Killifish, Sparkling Panchax, Striped Panchax). Southern India, northern Sri Lanka. 9-11 cm, females are generally slightly smaller. Lineatus are larger than panchaxes.
The body is elongated, the snout is slightly upturned, the mouth is large, the head is flat. The rear part of the body is slightly curved due to the strongly posteriorly shifted dorsal fin. The caudal fin is fan-shaped (rounded). The anal fin is large. On the upper side of the head, there is a well-noticeable light spot with a silvery sheen. Pelvic fins are elongated, several rays form threads.
Fish coloration varies greatly. The male is very bright — the torso ranges from olive-brown to dark green (darker on top), with 4-6 black transverse stripes running along the body. Juveniles and females have 9 such stripes. On the lower jaw, there is a longitudinal yellow or red-white stripe with a black edge. The lower belly, anal, and dorsal fins are yellow.
Coloration heavily depends on the angle of incidence of light and its spectrum. In lateral sunlight, fishes look very bright, as if they are “burning” with a yellow-green fire. Males are brighter than females and the stripes on their body are wider. Pectoral fins in males are elongated. Females are colored rather dull, smaller and darker than the male, have more stripes, and transparent fins. The main body color is gray, with short rows of shiny bronze-gold scales on the front part of the flanks.
Pelvic fins are shorter than in the male and colored in whitish or pale yellow tones. Unpaired fins are transparent with soft yellowish-orange edges, more rounded. Under stress, especially in young specimens, a wide dark gray stripe along the body may appear.
Three color variations are known — the natural form has 6 to 8 dark transverse stripes on a silvery body. The second form is the “Gold” variety. The main color of the body and unpaired fins of the male is bright lemon-yellow. The largest and intensely colored scales are located on the front part of the flanks, but closer to the tail the coloration remains very ornate. The back is colored in gray tones, the belly is lighter. Pectoral fins are transparent with a slight yellowish tint. Pelvic fins are colored the same as unpaired ones.
The third form has magnificent coloration. A large red dot is located on each scale, making the fish’s coloration golden-red. Red dots in males are larger and brighter than in females. Fins are colored from red to yellowish. However, full coloration develops only upon reaching sexual maturity — around 6 months at a body length of 6-7 cm.
These fishes do not show aggression towards other aquarium inhabitants and can be considered peaceful; they are not territorial and do not chase slow neighbors. Intraspecific aggression is also not typical for them, so keeping several males in the same aquarium is quite acceptable. It is advisable to keep one male and several females.
When keeping several males in one aquarium, you can observe how they “settle differences” with each other. Unlike many species of aquarium fishes, in aplocheilists this happens absolutely peacefully. In case of danger, they try to hide in thickets or near the surface in the corner of the aquarium, turning their heads toward the “disturber of peace”.
They do not like bright lighting. They stay in the upper layer of water — preferring to stand, waiting for prey, under floating plants. With proper feeding, they get along wonderfully with large characin fishes. Very small fishes, such as tetras or fish fry, may well be perceived as food. Adult fishes are able to eat an adult female zebrafish.
Areas of dense vegetation, loves floating plants. Jumpy, the aquarium must be covered. Suitable for keeping in a mixed aquarium, without small fishes, with a dark sandy substrate and driftwood for cover. Undemanding to water composition — fishes live wonderfully in both hard and soft water, preferably with a neutral or slightly acidic reaction (pH 6.7-7.0) and a small amount of dissolved organic matter. The presence of salt in the aquarium, both for medicinal purposes and as a preventive measure, is easily tolerated by the fishes — they withstand salinity up to 10 g/l without visible damage.
They love clean water with a temperature of 22-25°C (extreme values — 20 and 28°C). It is not recommended to lower the temperature to 20°C, at which fishes lose their appetite and susceptibility to fungal diseases increases. Pikes are resistant to a wide range of diseases and rarely get sick. Sexual maturity depends on water temperature and feeding — 3-8 months. Spawns eggs on plants. Lifespan is 3-5 years. pH 6-7; dH 8-20°.
Identification: Aplocheilus lineatus.
— Aplocheilus panchax [Hamilton & Buchanan, 1822] — Blue Panchax, Madras Pike, Aplocheilus panchax. Code: PAN. Synonym: Haplochilus panchax. (Eng- Blue Panchax Killifish. Chocolate Lyretail Kill). The habitat occupies a huge territory, which includes almost the entire India, part of Thailand, and some islands of the Indian Ocean.
Such an extensive distribution area gave rise to assumptions about the reproductive isolation of individual populations, and based on this, several subspecies were identified: — A. panchax andamanicus (Code: AND), — A. panchax mattei (Code: MAI), — A. panchax lutescens (Code: LUX), — A. panchax marginatus (Code: MAN), — A. panchax dorsomarginatus (Code: DOM) and — A. panchax siamensis (Code: SIA).
External features that allow classifying fishes to one subspecies or another are mainly the amount of yellow and red pigments on unpaired fins, coloration, and size of adult specimens. Up to 8 cm. The dorsal fin is small and located quite far behind the middle of the back. The high and long anal fin is also shifted backward. Together with the caudal peduncle, they form a single wide plane necessary for more effective propulsion when jumping for insects, which fishes feed on in nature. The body is elongated, flattened on top, which makes it somewhat resemble a pike. The mouth is superior. The fins of panchax males compared to A. lineatus are more rounded, pelvic fins are short in both females and males.
Fish coloration varies greatly. There are many differently colored breeding forms. The basis of the male’s attire consists of greenish-steel colors, with a violet sheen in reflected light. The back is gray, there is a large shiny spot on the head, the belly is yellowish. Rows of faint red dots run across the body. Each scale is bluish with a dark border. Speckles are also present at the base of the anal and caudal fins. A black border is often present on the caudal fin.
The coloration of unpaired fins can range from pure white to orange-red. There is an orange edge on the dorsal and anal fins. A black field is located at the base of the dorsal fin. The male is slightly brighter and larger than the female. The female is colored more modestly, body sheen is practically absent, fins, especially in the white color variation, are colored pale. The edge of the anal fin in females is more rounded than in males, and the belly in females is fuller. The female’s caudal fin is round.
Lively, peaceful fish that stays in the upper water layer in the current created by the filter. When frightened, they easily leave the aquatic realm and can jump out even through a very small gap. They descend to lower water layers only when hungry — in search of food. Kept in spacious mixed aquariums with fishes of approximately the same size. Males are distinguished by a pugnacious temperament, can be kept only with large species. In a general aquarium, males often settle scores, widely spreading their fins and protruding their gill covers downward. However, these tournaments do not have serious consequences. Males do not show aggression towards females.
They are undemanding to water parameters, can live in regular tap water as long as it has been aged, is warm (not lower than 22°C), and has a reaction close to neutral. Feeding adult fishes should be regular and varied. Very resistant to various kinds of diseases. Fishes reach sexual maturity at the age of 2-4 months. Lifespan is 3-5 years. pH 6-7.5; dH 4-12°; T 21-23°C.
Pachypanchax omalonotus, playfairii, sakaramyi.
Toothcarps in nature, Diseases of toothcarps. 
