In historical literature I have run across the name "Lafayette" when it came to fish a number of times but have to admit I have never heard of a Lafayette fish before. I ran across a little article in a 1915 Forest & Stream and it explained where this name derived, and then a little research showed me what the modern fish is actually named.
HOW THE LAFAYETTE WAS NAMED
Q: Editor, Angling Department: Can you tell me how the fish called 'Lafayette' received its name? J.T.R., Alfred, N.Y.
A: According to Louis Rhead, the name 'Lafayette' was given to this fish by fishermen around New York, on account of its reappearance in large numbers in the region coincident with the arrival of Lafayette in this country in 1824.
President James Monroe invited Revolutionary War hero (and French Revolutionary War hero as well) the Marquis de Lafayette to visit America in February, 1824. The Marquis accepted and arrived to great fanfare in New York City in August of that year. His sixteen month tour of the nation culminated in a speech he gave before Congress in December 1825--the first foreign national to address that august body. Congress rewarded Lafayette for his service to the nation with a $200,000 grant (approximately $4.3 million today), which since he was virtually impoverished allowed him to live the rest of his days in comfort. Who says the U.S. doesn't treat its heroes well?
The fish that so flourished in 1824-1825 became known as the Lafayette in his honor. Today, Leiostomus Xanthurus is better known as just a Spot, Norfolk Spot or Spot Croaker. It is a tiny seagoing fish of around 5-10 inches in length. They were a popular table fish in the 19th century eaten and served like sardines, and it is likely a few people on the East Coast still honor Lafayette's memory by attaching his name to this fish.
-- Dr. Todd