Just like the Rooster Tail, Mepps is a trout spinner bait that has been catching fish for decades. The Aglia series is the most popular when it comes to trout fishing, consisting of ultra-light spinners, plain spinners, and those dressed with bucktail, flashabou, or even a fly. This vast array of options helps make it one of the best spinners for trout. So out of all these options, you may be asking what size spinner for trout? The ultra-lite series is perfect for stocked trout in smaller bodies of water, while the other series come in many different sizes appropriate for any size fish, lake or river you might be fishing.