Of fish, it was only the larger species which they caught, like the salt-water trout and the "red fish," which resembles the codfish. They never used nets or angling lines. Of turtles, the great green turtle, often 3½ feet long, was brought by them to the shore alive and then killed and eaten. The lagoons teemed with porpoises, but the Indians did not hunt for them.
Fish were abundant, — red-fish, sea-trout, flounders, sheep's-head, Spanish mackerel and Jew fish. The Indians took their fish by the same weapons with which they hunted their game, viz. : the bow and arrow, and they were remarkably expert in this way of fishing. Whether in their canoes, or while standing in the water after wading out hip-deep, no matter how turbid or rough the water might be, their aim was unerring; holding their arrow in place with drawn bow and watching intently, suddenly " the arrow flies and the fish dies," and then as it rises to the surface it is easily secured.
Often when the white people had tried in vain with their hook and line, the Indians with their trusty bow never failed to capture a fish. It seems that they could feel the approach of a fish in roiled water by the motion or undulation of the water below the surface.
More information on the Karankawa
Karankawa Tribe near Goliad
The Karankawa Indians
Ennis Joslin Indian Burial Ground
Indian Burial Ground (Dietz Archeological Site)