The world's smallest fish is the Paedocypris fish, which can fit on the tip of your finger

Paedocypris fish is a tiny fish species that was discovered in 2006 in the Indonesian island of Sumatra. It is considered the smallest fish in the world, with adult individuals reaching a maximum length of 7.9 millimeters, or about the size of a small mosquito. The fish’s small size is believed to be an adaptation to the highly acidic waters of its habitat, which is characterized by the presence of peat swamps. Despite its diminutive size, the Paedocypris fish has a complex anatomy and exhibits several unique adaptations, such as specialized fins and teeth for feeding on small invertebrates. The species is of scientific interest due to its potential use as a model organism for studying vertebrate biology and development.

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