If you are in the central Pyrenees or planing to go, there is one guide you want to fish with, on the Spanish side. He is the best. He is nice, patient, amazing fly fisherman and knows all the streams and rivers of the aera like the inside of his waders! Marc Vande Vliet is from Belgium but he moved to Catalunya more than 2 decades ago. He coached the Belgian fly fishing team and speaks English fluently. His new website is up and if I was you and that I was planning to come to Europe or if you are in Europe and planning to fish in the Pyrenees, I would check it out! Trust me, he is Mouching approoved!
What I do and maybe you should do the same, is when I go to Spain for summer holidays, I manage to go fishing a few days with him. A few days at the beach, a few days in the moutains, fishing. You should check his new webpage!