Climbs to get fishy plates (6)
I believe the answer is:
scales
This might be a double definition.
'climbs' is the first definition.
(scaling is a kind of climbing)
'fishy plates' is the second definition.
'scales' can be an answer for 'plates' ('scale' can be a synonym of 'plate'). I am unsure of the 'fishy' bit.
'to get' acts as a link.
Can you help me to learn more?
(Other definitions for scales that I've seen before include "The practice of music" , "is a climber" , "though it's not Pisces" , "Instruments for weighing things" , "Set of musical notes - balanced on a fish?" .)