No ordinary eel can be said to dance! (6)

I believe the answer is:

conger

I'm a little stuck... Click here to teach me more about this clue!

'no ordinary eel' is the definition.
'conger' can be an answer for 'eel' (conger is a kind of eel). I am not sure about the 'no ordinary' bit.

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for conger that I've seen before include "Large sea fish of the eel family" , "Large, strong eel" , "Large 23" , "slippery character" , "A large fierce eel" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app