Golden Wonder Killifish
Aplocheilus lineatus
A hardy golden surface predator that will eat small fish but dazzles in planted tanks.
| Difficulty | Beginner |
| Min. Tank Size | 75 L |
| Temperature | 22.0–26.0 °C |
| pH Range | 6.0–7.5 |
| Max Size | 10.0 cm |
| Lifespan | 3-4 years |
| Diet | Carnivore |
| Temperament | Semi-aggressive |
Overview
The Golden Wonder Killifish (Aplocheilus lineatus) is a hardy golden surface predator that will eat small fish but dazzles in planted tanks. It is a popular choice among Australian aquarists, reaching around 10 cm and living roughly 3-4 years when properly cared for.
This complete guide covers how to keep the Golden Wonder Killifish successfully - tank size and setup, water parameters, the best foods (including recommended brands), suitable tank mates, breeding, sexing and the health issues to watch for. It is rated Beginner to care for.
Natural Habitat & Origin
Killifish inhabit small, soft, often shaded pools, streams and swamps. Many are surface-dwellers, so a tight lid is essential as they are accomplished jumpers.
Matching the temperature, water chemistry and cover a species evolved with is the simplest route to keeping it healthy and seeing its natural behaviour and colour.
Tank Size & Aquarium Setup
Provide a minimum of 75 litres for the Golden Wonder Killifish. A roomy, well-decorated tank lets a pair settle and behave naturally.
A tight-fitting lid is essential - this species is a capable jumper.
Live plants, driftwood and shaded retreats give security and show off the fish's colours against a natural backdrop.
Always add fish only to a fully cycled, mature tank with stable biological filtration. Match filtration generously to the fish's size and waste output.
Water Parameters
Keep the Golden Wonder Killifish in stable water at 22-26 °C with a pH of 6.0-7.5. It adapts to a moderate range, so stability matters more than an exact figure.
Test regularly: ammonia and nitrite must read zero, and nitrate should be kept low with routine partial water changes. Always dechlorinate and temperature-match new water, because sudden swings cause far more illness than water that is stable but slightly imperfect.
Diet & Feeding
The Golden Wonder Killifish is a carnivore and needs a protein-rich, meaty diet.
In Australia, good options include Hikari Carnivore pellets or Vibra Bites, plus Dymax frozen bloodworm, daphnia and brine shrimp. Feed small amounts once or twice a day (only what is cleared in a minute or two), vary the diet for the best colour and health, and avoid overfeeding, which is the leading cause of poor water quality.
Temperament & Tank Mates
The Golden Wonder Killifish is semi-aggressive: generally community-tolerant but territorial at times, especially when breeding or under-stocked. Avoid very small, slow or long-finned tank mates and give everyone space.
Breeding
The Golden Wonder Killifish is an egg-scattering species. To breed it, condition a group on rich foods, then move them to a dim tank with fine-leaved plants or a spawning mop; the parents scatter eggs and will eat them, so remove the adults after spawning.
Even if you are not planning to breed it, recognising this behaviour helps you understand what you are seeing and respond well - for example by adding cover for fry or giving a guarding pair extra space.
How to Tell Males from Females
Males are dramatically more colourful with longer, more elaborate fins, while females are plainer and rounder - sexing is easy.
Common Health Problems
Like most aquarium species it can suffer from white spot (ich), fin rot and fungal or bacterial infections, almost always triggered by stress or poor water quality. Quarantine new arrivals for 2-4 weeks and watch daily for early signs such as loss of appetite, unusual hiding, clamped fins or laboured breathing - caught early, most issues are very treatable.
Prevention beats cure: keep water pristine, avoid overstocking and overfeeding, quarantine new arrivals, and act at the first sign of trouble.
Is the Golden Wonder Killifish Right for You?
The Golden Wonder Killifish suits beginners and experienced keepers alike, as long as you can provide at least 75 litres, water at 22-26 °C and pH 6.0-7.5, the right diet and suitable tank mates.
Meet those needs and the Golden Wonder Killifish will reward you for around 3-4 years. Use our free aquarium calculators to plan your setup, and explore our other fish, plant and disease guides to build a thriving aquarium.