Planarian Starter Culture

Dugesia polychroa is a common European freshwater planarian (free-living flatworm) distributed across clean ponds, streams, and lake edges throughout Europe and parts of Asia. Unlike parasitic flatworms, planarians are entirely free-living and harmless to aquatic animals in a hobbyist context. They glide smoothly across hard surfaces using cilia and can detect food through chemoreception, making them fascinating to observe.

As a live food, planarians provide an excellent protein and fat source for fish fry, small predatory fish, and carnivorous invertebrates. They can be cultured indefinitely in simple containers with regular feeding of small amounts of meat or liver, a cool temperature, and regular water changes. Their extraordinary regenerative ability — a bisected worm becomes two complete individuals — makes them a perennial favourite for biology education.

For aquarium use, planarian cultures should be kept separate from shrimp tanks, as planarians will occasionally prey on very small shrimp juveniles or freshly molted individuals. However, they pose no risk to healthy adult shrimp or fish.

Water: 15–22°C; dechlorinated freshwater; pH 6.5–8.0; cool temperatures extend lifespan. Tank: culture container 2–10 L, glass or food-safe plastic, no substrate needed, dim conditions. Feeding: small portions of beef liver, shrimp, or egg yolk every 3–5 days; remove uneaten food. Breeding: asexual fission and sexual; culture expands rapidly with adequate food and temperature. Compatibility: separate from shrimp; harmless to healthy adult fish; useful live food supplement.