Bleak

The Bleak is a small, slender, surface-oriented cyprinid found in large rivers, canals, and lake margins across Europe. Its silver, highly reflective scales historically made it commercially valuable — the iridescent substance (essence d'Orient) scraped from its scales was used to make artificial pearls.

In the aquarium bleak are active, surface-schooling fish that constantly patrol the upper water column. They are well-suited to a long European river biotope tank with good oxygenation and moderate flow. Their upturned mouth is adapted for surface feeding.

Bleak are peaceful and do not compete aggressively for resources. Their constant movement and flashing silver scales create a dynamic, visually appealing display.

Water: 5–22°C, pH 6.5–8.0, GH 5–18; good oxygenation, moderate surface current preferred. Tank: minimum 150 L, long tank, surface access, tight lid as they can jump when startled. Feeding: omnivore — floating flake, frozen daphnia, cyclops, small insects. Breeding: spring spawner over gravel in shallow water; requires large space and seasonal cycling. Compatibility: peaceful; excellent with other European schooling cyprinids and benthic species.