Possible Clues:

• In water, inside 21 down (3)
• Most of what's left is in water
• New T would not be right to follow L
• One foot in the water under the East
• Juvenile twenty-three Ac; rhymes with sinister
• Is there just a little bit at the end of what's left in the water?
• Payment made via computer: abbr.
• Tiny wriggler
• The little creature would get abandoned after half a century
• Swimmer with feeble legs needs some beef tea