Indonesian Swamp Yields Smallest Fish

Scientists have discovered the world’s smallest fish on record, with a see-through body and a head that is unprotected by a skeleton, in an acidic peat swamp in Indonesia, researchers said Wednesday.

Mature females of the Paedocypris progenetica, a member of the carp family, grow to 0.31 inches, and the males have enlarged pelvic fins and exceptionally large muscles that may be used to grasp the females during copulation, according to the study published Wednesday in the Proceedings of the Royal Society B. The fish live in dark, tea-colored water with an acidity of pH 3, at least 100 times more acidic than rainwater.