Chinese Red-tailed Bitterling Acheilognathus tonkinensis

Chinese Red-tailed Bitterling are native to rivers and streams of southern China, northern Vietnam and Laos. They are well-camouflaged among the stones of their habitat and grow to 12cm long. Unusually for fish, but usual for bitterlings, females have an extendable ovipositor which they use to lay their eggs in freshwater mussels; the male then releases sperm to the open mussel and when the fry hatch, they remain protected in the mussel until they can swim freely.