Smallest organisms with mature females measuring as little as in standard length. This fish, a member of the carp family, has a translucent body and a head unprotected by a skeleton. The one of world's smallest fish based on the minimum size at maturity is "Schindleria brevipinguis" from Australia,their females reach it at 7 mm (0.28 in) and males at 6.5 mm (0.26 in), Males of "S. brevipinguis" have an average standard length of , a gravid female was . This fish, a member of the goby family,its first anal-fin ray further forward, under dorsal-fin 4. Male individuals of the anglerfish species
Smallest organisms that lives between sand grains on the coast of India. Its maximum length is only 4 mm. The smallest sea urchin, "Echinocyamus scaber", has a test only 6 mm across. "Patiriella parvivipara" is the smallest starfish, at only 5 mm across. The smallest vertebrates (and smallest amphibians) known are "Paedophryne amauensis" frogs from Papua New Guinea, which range in length from , and average . Previously, the title of smallest vertebrate was held by members of the fish genus "Paedocypris" of Indonesia. The one of world's smallest fish based on the minimum size at maturity is "Paedocypris progenetica" from Indonesia,