i made the fishing poll but i still cant fish out the item in the pool what do i do 

hey! I got the same issue. If you found a way to make it work please let me know. I am stuck at the same place.

If I understand correctly, you opened the pool then went with the fishing rod in your inventory back to the pool and then fished the item out? if so, you did everything correctly. After that, it is no longer possible to fish in the pool