The Rainbows you caught were planted just hours before, on the same day. https://wdfw.wa.gov/fishing/reports/stocking/trout-plants/all?lake_stocked=AMERICAN+LK+%28PIER%29&county=Pierce&species=&hatchery=®ion=&items_per_page=25 They don't give them breakfast so they will be hungry and bite on almost any lure- colored string +hook included. They do fight a lot considering it was their first one, full of vim/vigor like any youngster. The red colored meat is an additive they add to their food weeks before stocking the lakes; https://www.longdom.org/open-access/retention-of-fillet-coloration-in-rainbow-trout-after-dietary-astaxanthin-cessation-2150-3508-1000163.pdf Your fish in the live well-swimming belly-up are in shock (oxygen starvation)- all kinds of natural chemicals running through their blood to taint the flesh. This leaves an off-taste in the meat. Better to kill those stressed ones---- then right away, gut and clean the blood line next to their spine to enhance the flavor from bad to normal or less. (For a fresh planted hatchery raised fish) You wouldn't add them back in the well of surface temperature water- need these next to ice to keep the meat cold; https://extension.umn.edu/preserving-and-preparing/preserving-fish-safely They are fun, aren't they!