As far as I know, there are no fiberglass tenkara rods. I have tried to use a fiberglass panfish pole to fish in the tenkara style, and it was much too whippy. There is a composite carbon/glass rod in the works but I don't know when it will be on the market.

There is no need to tape the joints. Since the rods are telescopic, with the sections closer to the tip fitting inside the sections closer to the butt, they cannot be pulled apart. When you extend the rod, it only takes a VERY little bit o force to seat them well enough that they will not collapse of their own accord when you raise the rod tip.