Tench

The Tench is one of Europe's most widespread native freshwater fish, found in lakes, ponds, and slow rivers from England to Siberia. Its distinctive olive-green colouration, tiny scales covered in protective mucus, and characteristic orange eyes make it instantly recognisable.

The folk name 'doctor fish' derives from the belief that other fish rub against the tench's mucus coating to heal wounds — a legend, but indicative of the mucus's unusual properties. In the aquarium Tench are peaceful, efficient scavengers that work the substrate for leftover food.

Best suited to a large coldwater aquarium or pond, Tench grow large over time and require excellent filtration. The Golden Tench variety, with bright orange colouration, is also available.

Water: 5–25°C, pH 6.5–8.0, GH 5–20; tolerant of poor conditions but thrives in clean water. Tank: minimum 500 L for long-term keeping; fine sand substrate; powerful filtration essential. Feeding: omnivore — sinking pellets, earthworms, bloodworm, and blanched vegetables. Breeding: spring spawner over aquatic vegetation; requires seasonal temperature cycling and large space. Compatibility: peaceful with all fish too large to be eaten; good tankmate for other large European species.