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 with a length of 0.37-0.89 μm and an average cell diameter of 0.12-0.20 μm. They also have the smallest free-living bacterium genome; 1.8Mbp, 1354 protein genes, 35 RNA genes. They are one of the most common and smallest organisms in the ocean, with their total weight equaling more than all fish presently in the sea. "Mycoplasma genitalium", a parasitic bacterium which lives in the primate bladder, waste disposal organs, genital, and respiratory tracts, is thought to be the smallest known organism capable of independent growth and reproduction. With a size of approximately 200 to 300 nm, "M. genitalium" is an