The Dolly Llama in Olive/White is a streamer fly from RIO, offered in hook sizes #2 and #6. Its two-tone olive and white color scheme suggests a baitfish profile in the water.
Streamers like this are fished with an active retrieve to imitate fleeing baitfish, making them a strong choice when targeting aggressive trout. Pick the #2 for bigger water and larger fish, or the #6 for a smaller presentation.
