Just because a #2 bamboo needle fits between the slots in the water feature pump DOES NOT mean that it will pull out the cotton wood fluff that is impacted in there. Very possibly it will get out a few bits of wet cottony mess before cracking and breaking off. You will need a needle nose pliers to get that needle out of there.
Just start out using the pumpkin carving knife. You know the one - the little orange handled thing that came in the kit from Target. Those little jagged edges will grab onto that yucky stuff right away.