You do not have a big problem. It's a pond not a swimming pool. Rake it out before it sinks to the bottom and decomposes.

Also a lot of food organisms for smallest fish grow on and among the strands of algae. Things like small zooplankton and other invertebrate type animals live among the strands of the algae. Small fish hang out there for the food buffet and shelter.

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management