The reason why Salmon has red colored flesh!
In the wild, salmon get their red color from carotenoid pigments found in marine algae, this is the same algae that causes the red in red tide.  This algae is consumed by crustaceans and small fish, which in turn is consumed by the salmon.  The amount of red pigmentation absorbed in its flesh is a function of both diet and genetics.

The story of farm raised Catfish begins in the late 1960’s, when a handful of Mississippi rice farmers started experimenting with Channel Catfish fingerlings.  After a number of soybean crop failures in the early 1980’s, catfish gained in popularity and became the alternative crop.  Mississippi is the largest producer, with Texas being the largest consumer.
The world’s smallest fish is the half inch long Dwarf Goby from the Indian Ocean.
The worlds largest confirmed Sturgeon was a 4,500-pound fish caught in the Caspian Sea, with unconfirmed catches even larger.
The documented history of Tuna dates back to pre-historic times.  In Europe, the caveman honored it with etchings on the walls of his dwelling.  Phoenicians caught them in traps 3,000 years ago and marketed them throughout the ancient Mediterranean world.  Monetary coins from Carthage and Cadiz even had tuna pictured on them.