Possible Clues:

• Grain scattered in enclosure for fish
• Fish in small can poet finishes
• Fish with a formidable barbed dorsal spine on its tail
• Mean to eat bream every so often, as fish
• Mean to protect river area for fish
• Mean to collect water, dropping in fish
• Flatfish
• Ocean-bottom hider
• Marine creature with venomous tail
• Ring around, getting involved in support for swimmer