Stories about regularly adept or developing little swimmers (8)
I believe the answer is:
tadpoles
'little swimmers' is the definition.
(I've seen this before)
'stories about regularly adept or' is the wordplay.
'stories' becomes 'tales' ('tale' can be a synonym of 'story'**).
'about' indicates putting letters inside.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'adept'+'or'='adeptor'
The alternate letters of 'adeptor' are 'dpo'.
'tales' placed around 'dpo' is 'TADPOLES'.
'developing' is the link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for tadpoles that I've seen before include "Larvae of frogs or toads" , "Baby frogs" , "Young frogs" , "Immature frogs" , "Pond-life" .)