Related Clues:

• Fish tank organism
• Underwater forest plant
• Kelp, for one
• Rootless water life
• Ocean algae
• Pool microorganism
• Tiny pond organism
• Bit of aquarium growth
• Badderlocks, for one
• Bit of phytoplankton
• Lichen component
• Tiny aquatic organism
• Oxygen releaser
• Unwanted plant in a pool
• Agar source