What is the smallest aquarium fish (freshwater tropical)?

Scaturiginichthys vermeilipinnis - Red-finned Blue eye grows to about 2.5 cm and is native to Western Queensland, Australia and then there's the smallest fish in the world found in Indonesia in Sumatra, the Paedocypris progenetica is officially the world's smallest fish at only 7.9mm long, that is less than 1/3 of an inch in water that has a PH level of 3. This is about 100 times more acidic than regular rainwater! This discovery was made in 2006. But, I doubt if you'll find any of these at your local pet store. I would have to say that the bumblebee goby or an endler guppy would be about the smallest fish available for the home aquarist.  more