Crucian Carp

The Crucian Carp is native to still and slow-moving waters across Europe, from England to the Ural Mountains. It is perhaps the most cold-tolerant freshwater fish in the world, able to survive months trapped under ice through anaerobic metabolism — producing alcohol as a by-product instead of toxic lactic acid.

In the aquarium Crucian Carp are peaceful, undemanding, and longlived. Juveniles are attractively deep-bodied and golden-bronze in colour. They are best appreciated in a large aquarium or pond biotope replicating a European lake or oxbow.

This species is a true conservation interest, as pure Crucian Carp are increasingly rare in the wild due to hybridisation with Goldfish and Prussian Carp. Keeping pure-strain fish supports awareness of the species.

Water: 4–23°C, pH 6.0–8.0, GH 4–20; exceptionally tolerant; survives oxygen depletion under ice. Tank: minimum 300 L for juveniles; best in ponds or very large coldwater aquariums long term. Feeding: omnivore — sinking pellets, earthworms, blanched vegetables, daphnia. Breeding: spawns in spring over submerged vegetation; requires large space and seasonal temperature cycling. Compatibility: peaceful with all similarly sized fish; avoid mixing with Goldfish to preserve genetic purity.