it is extremely difficult to determine the age of a fish once past the juvenile stage (usually around 6 months of age). up to this age, fish age can be exactly identified, even down to the day they were spawned using "ooliths." these ooliths (3 in total) are tiny calicum carbonate structures responsible for balance and sound detention. the protiens within these ooliths are extremely similiar to growth rings on trees. unfortunitely, once past 6 months of age, these ooliths are of little help, and biologists don't have any other accurate way of measureing a fish's age. most common is the length-frequency analysis, which is unfortunitely also the least effective method. a tag and recapture method can be helpful, but again, has shortcomings. simply put, we don't have any accurate way of measuring the age of fish once they've become adults.
a few simple generalizations can be made, however. first off, the larger the fish, the longer it lives; and thus conversely the smaller it is, the shorter it lives. warm water fish also seem to have a shorter lifespan than cold water species.
now, even though we cannot get an exact age, i must disagree with the notion that Gobiosoma sp
. have a 1 year lifespan. i suspect the fish can live up to 3 or 4 years old, but i doubt they can live any older. FWIW, have several Gobiosoma sp
. that are over 2 years old. we'll see how long they can hold on
FWIW, some biologists believe that the smallest gobies and blennies live a single season, while the oldest known reef fish is also the largest, Epinephelus itajara
, or the jewfish, being aged to 37 years.