I don’t know to be honest! I remember Ozge mentioning that the combined total biomass of all the Krill in all the Oceans in the world (i.e. the weight of all of them put together) would be more than that of any other creature in the Ocean, maybe even the entire world! Crazy huh? Krill are only very small though so there muct be a lot of them.
However, Krill aren’t fish so that doesn’t answer your question… I think i’ll have to rely on a very reputable source for this one. The National Oceanographic and Atmospheric Administration (some very important American bods… quite knowledgable about this sort of stuff) website reliable informs me that the most common fish in the sea is…
“Any of the several species of Cyclothone, a deepwater fish sometimes called a “bristle mouth.” Rarely visible at depths that man can readily reach, the fish is about the size of a small minnow. It is netted at 500 meters or deeper all over the world”
Cyclothone? No, me neither… Hope that answers your question!