The researchers studied how different fish species affect the growth of tiny plants in pearl mussel ponds. They found that ponds with only mussels had more plants than ponds with lots of silver carp. Ponds with mussels also had more cyanobacteria, a type of plant, than ponds with silver carp or bighead carp. Adding bighead carp or silver carp to mussel ponds helped control algae and promote the growth of other plants. More silver carp in a pond led to less plants overall, while more bighead carp helped a specific type of plant called Euglenophyta grow.