Related Clues:

• Fishtank organism
• Seaweed found in local garage
• Kelp, e.g
• Bit of fish food
• Sow around wonder that grows in pools ...
• Seaweed found in the botanical gardens
• A single one of those things you see floating in the pool when you don't clean it
• Seaweed or kelp
• Photosynthesizing aquarium denizen
• Pool growth
• Minuscule lake organism
• Tiny tank plant
• Bit of pond slime
• Source of agar
• Kelp, for example