Was looking around web a bit ago trying to find resonable explanation of why so many reef fish are "spotted" with a wide range of colors...camouflage, attraction, differention of similar shaped fish...

...
Anyway as reading article (
A Note About Fish) which claimed,
"...The smallest fish is the
Trimmatom nanus, a goby of the Indian Ocean, which grows to about 2/5 inch (1 centimeter) long..."
Trimmatom nanus
Thinking that was pretty darn small, got to looking around to see what it looked like, and found it is now the 3rd smallest fish...
re:
Trimmatom nanus
From
Wikipedia, the free encyclopedia
Trimmatom nanus is a species of marine fish in family Gobiidae of Perciformes. It is the type species of its genus. One of the fishes called dwarf gobies, it is native to the Chagos Archipelago and the Maldives in the western Indian Ocean.
With adults growing to a total overall length of just over 10 mm (less than one-half inch), T. nanus was until 2004 the shortest known fish and vertebrate. The recent discovery of S
chindleria brevipinguis (called the stout infantfish) relegated it to second place. After discovery of
Paedocypris progenetica, Trimmatom nanus is on third place.
Stout Infantfish - Schindleria brevipinguis
Guess above was smallest till 2006...
re:
World's smallest fish found in Indonesia (MSNBC)
(AP - updated 11:24 a.m. PT, Wed., Jan. 25, 2006)
BANGKOK, Thailand - "...Scientists have discovered the world's smallest fish on record in an acidic peat swamp in Indonesia, with a see-through body and a head that is unprotected by a skeleton, researchers said Wednesday.
Mature females of the
Paedocypris progenetica, a member of the carp family, only grow to 7.9 millimeters (0.31 inches) and the males have enlarged pelvic fins and exceptionally large muscles that may be used to grasp the females during copulation..."
(Just in case you are looking for something to go into your "Mini Micro Pico"

)