Rosy bitterling

The rosy bitterling is a small freshwater cyprinid (family Cyprinidae) native to East Asia, including parts of China and introduced widely elsewhere. Breeding males develop a pink-to-purple iridescent flush and colorful fins, while females are plainer silvery and develop a long ovipositor tube when ready to spawn. It is a peaceful, sociable shoaling fish suited to subtropical and coldwater community tanks. It is best kept in a group and mixes well with other temperate species. Its most remarkable feature is its breeding biology: the female uses her ovipositor to deposit eggs inside the gills of a living freshwater mussel, where the young develop protected, so a healthy mussel is required for spawning. It is an omnivore that grazes on algae and small invertebrates and accepts flake, frozen, and live foods. It thrives in cool, well-planted aquaria or ponds.