Golden Wonder Killifish

Geographic Origin and Biotope: 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.

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 Tankmates: 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 Reproduction: 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.