Baby frog (7)
I believe the answer is:
tadpole
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">baby frog</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for tadpole that I've seen before include "Frog in the making" , "Amphibian larva" , "little swimmer" , "Baby amphibian" , "Old tape (anag.)" .)