The Case of the Yucky Slime

S1 E3: Fishtronaut, Marina and Zeek discover a trail of slimy stuff running through the park. What could it be? During their mystery-solving journey, they notice that visitors have been cutting down bushes and trees to create a canoe lagoon and don't realize the harm that this erosion can do to the lake. To help the water to be healthy again, the gang replants along the shoreline.