Although several nice versions of this Prichard & Knoll trade card with novelty fish lettering were produced in the later 19th century, you might say they are now endangered.
These two came from the same dealer and recently sold at auction for handsome sums. They are equally nice, however the first card has much finer detail held in the rainbow trout artwork and fish lettering.
It was printed by Stahl & Jaeger Artistic Lithographers in NYC. The second card has the name reversed and several alternate letters, along with some clever wave-like handlettered text with flourishes below the fish which add to its appeal.
They each have an eel ampersand.
Directly below is another unrelated trade card from 1871 with similar novelty lettering of fish.
This particular card from Fisher Ice Boxes and Refrigerators of Chicago, found here, is sporting an amphibious eel for the letter S. Although this Fisher card is nowhere near as elaborate as the two above, the artist did provide some level of detail to the three-colored fish.
I guess the imaginative art of fish lettering requires a fine line and some reel angling, just like fishing.