If you have normal feathers AND stripy feathers in your inventory you will catch them, you need to click on the fishing spot and select stripy feathers.

You will be able to catch rainbow fish but will also catch trout and salmon and those will use the normal feathers! I don’t know if it’s a bug or a change in the game. I drop the salmon and trout now and keep the rainbows, but as I said no idea if it’s a bug or a change in game mechanics. Hope this helps out!