Fishing kayak rentals and locations in Hawaii

Next June we are planning about a 10 day trip to Oahu and Kauai. I have never been to Hawaii at all, so it is all new to me. Please let the recommendations flow. Thank you!

Recommendation number one.... take me and my wife with you 
We have never been either!

On Kauai, right next to Da Crack (Google it) in Poipu was a kayak shop. I know they rented bikes and sold kayaks. Not sure if they also rent kayaks. I remember asking them questions about fishing when I was there a few years ago. I'm sure they could steer you to a rental.