Golden Wonder Killifish
Aplocheilus lineatus
The *Aplocheilus lineatus*, universally sold in its 'Golden Wonder' breeding variant, is an atypical killifish. Forget the tiny and delicate creatures of Africa: this is a burly and impetuous surface predator that reaches 10-11 cm (4.5 inches). The 'Gold' male sports a dazzling golden-yellow livery, while the wild form is striped. Unlike most killifish that require specialized care, the Golden Wonder is indestructible and adapts to any aquarium, as long as it does not house fish that can fit into its surprisingly large mouth.
Water Temperature
22 - 28 °C
pH Value
6 - 7.5
Water type
Freshwater
Tank level
Surface
Adult size
10 cm
Minimum tank volume
>= 100 L
Minimum group
>= 4
GH
5 - 15 dGH
KH
2 - 7 dKH
TDS
95 - 295 ppm
Conductivity
148 - 461 uS/cm
Species description
Geographical Origin and Habitat: Widespread in central and southern India, and Sri Lanka. Inhabits the surface waters of slow-flowing rivers, rice paddies, swamps and ponds, often taking shelter among the floating roots of floating plants.
Taxonomy and Morphology: Striped Panchax (Aplocheilus lineatus). It is a large Killifish (Cyprinodontiforme). It has a tapered "pike" shaped body in miniature, with an upward-facing mouth suited to grabbing prey on the surface.
Social Behavior: Formidable and calculating surface predator. Stations motionless under the water surface waiting for insects. It is peaceful with fish of its size, but will inexorably consider "food" any tankmate that fits in its large mouth.
Coloration and Sexual Dimorphism: Wild males are greenish-brown with golden scales and black stripes (lineatus) on the posterior half. There is a completely yellow-orange "Gold" breeding form. Females are paler, with rounded fins and more marked stripes.
Care, breeding and tankmates
Aquarium Setup: 80-100 cm (32-40 inches) tank. The use of an airtight lid is categorical: they are exceptional jumpers who aim at flying insects. Needs a tangle of floating plants (Pistia or Salvinia) to dim the light and limit surface current.
Diet and Feeding: Insectivore/Carnivore. Ignores food on the bottom. Devours crickets, drosophila, floating bloodworms and krill. Accepts granules and flakes, but the diet must be high-protein and administered exclusively on the surface.
Water Quality: Very robust and flexible fish. Adapts to neutral pH and moderately hard tap waters, but thrives with the addition of peat extracts. Resists seasonal temperature variations (22-28°C / 72-82°F).
Compatibility and Cohabitation: Incompatible with Neons, Guppies or small Rasboras (they would be swallowed whole at night). Excellent with Dwarf Cichlids (e.g. Pelvicachromis), Loricariids (Ancistrus) or medium-sized Barbs (Puntius titteya) that occupy different areas of the tank.
Aquarium Breeding: Non-annual Killi. Prolific spawners: lay large (about 2 mm) and hard eggs on wool mops or on the roots of floating plants. The eggs take 12-14 days to hatch. The large fry immediately devour brine shrimp nauplii.
Risks and Diseases: The only real risk in the aquarium is death by drying out caused by jumping out of the tank. Very resistant to common diseases if kept in well-filtered water without surface turbulence.
Geographic Origin and Distribution
Widespread in central and southern India, and Sri Lanka. Inhabits the surface waters of slow-flowing rivers, rice paddies, swamps and ponds, often taking shelter among the floating roots of floating plants.
Origin
Cosmopolitan or introducedAfrica and MadagascarSouth and Southeast AsiaTropical oceans and reefs
Fish profile
- Temperament
- Territorial
- This species is a peaceful ambush predator toward tank mates of similar or larger sizes, but can be highly territorial toward its own kind. Males in particular may display significant intraspecific aggression if the aquarium is too small or lacks adequate cover. It is crucial to remember that any small fish or invertebrate that can fit into its wide mouth will be perceived and consumed as prey.
- Diet
- Omnivore
- The diet of Aplocheilus lineatus should be primarily carnivorous and focused on foods that float on the surface. While they readily accept high-quality floating flakes or pellets, their health is best supported by regular supplementation with live or frozen foods. Offerings such as brine shrimp, bloodworms, daphnia, and small insects are ideal for stimulating their natural hunting instincts.
- Life expectancy
- 3-5 years
- In captivity and under optimal care, Aplocheilus lineatus typically has a lifespan of 3 to 5 years. Achieving their maximum life expectancy depends closely on receiving a high-quality diet and living in stable water parameters. Prolonged exposure to stress or keeping them in temperatures that are constantly too high can significantly shorten this duration.
- Adult size
- 10 cm
- The catalog's scalar value is 10 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 10 cm for this species, recorded as total length (TL). The taxonomic record consulted is Aplocheilus lineatus (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Harem
- It is highly recommended to keep this species in a harem structure, consisting of one male and two or three females. This ratio helps distribute the male's breeding interest and potential aggression, thereby reducing stress on individual females. In larger setups, multiple males can be kept together, provided there is sufficient space and visual barriers to establish territories.
- Feeding frequency
- Twice daily
- It is recommended to feed them once or twice daily, providing only the amount of food they can completely consume within a couple of minutes. Because they are greedy surface feeders, overfeeding should be strictly avoided to prevent digestive issues and water quality degradation. Implementing a weekly fasting day can be highly beneficial for maintaining their digestive health.
- Bioload
- Medium
- The biological load of Aplocheilus lineatus is classified as medium due to its predatory nature and high-protein diet. As a relatively large killifish reaching up to 4 inches (10 cm), it produces a moderate amount of organic waste that demands effective filtration. A gentle to moderate water flow should be maintained to accommodate their preference for calm surface waters, combined with weekly water changes of 15-20% to prevent toxin buildup.
- Flow
- Strong
- This species prefers weak to moderate water currents, which mimic its natural habitats of slow-moving streams, swamps, and rice paddies. A water flow that is too strong will disrupt their surface-hunting behavior and force them to exert unnecessary energy to remain stable. Using a filter with an adjustable flow rate or adding floating plants to break the surface current is highly recommended to create calm pockets of water.
- Jump risk
- Yes
- The jump risk for Aplocheilus lineatus is extremely high, as they are powerful and precise jumpers capable of leaping out of the water to catch insect prey. A tight-fitting aquarium lid with absolutely no gaps is mandatory to prevent accidental escapes. Introducing floating vegetation is highly beneficial, as it covers portions of the surface and provides a sense of security, which naturally minimizes their jumping behavior.
- Reproduction
- Oviparous
- Breeding this species in the aquarium is relatively easy and straightforward, even for less experienced aquarists. They are egg-scatterers that deposit adhesive eggs on vegetation or spawning mops suspended near the surface, usually triggered by warmer water and live foods. The eggs hatch in about 10 to 14 days, and the fry should be fed infusoria or freshly hatched brine shrimp nauplii as their initial food.
- Compatibility & tankmates
- With caution
- Compatibility is generally good with medium to large, robust tank mates that are not overly aggressive, such as larger barbs, medium-sized tetras, and peaceful bottom-dwelling catfish. Keeping them with tiny fish like neon tetras, guppies, or small shrimp must be strictly avoided, as these will quickly become prey. Other surface-dwelling or highly competitive species may also cause stress, so pairing them with fish that occupy the middle and bottom zones is ideal.
- Tank level
- Top
- Aplocheilus lineatus is a specialized surface-dwelling fish that primarily occupies the top level of the water column. Its physical structure, featuring a flat dorsal profile and an upward-pointing mouth, is perfectly adapted for life and hunting at the water's surface. While it spends the vast majority of its time near the top, it may occasionally descend to the middle levels of the aquarium to feed or escape perceived threats.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 3.8 ± 0.5 se
- Phylogenetic uniqueness (PD50)
- 0.5079
- Bayesian Length-Weight
- a = 0.00389, b = 3.12
- VulnerabilityLow vulnerability (10 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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