Fish bite on river Tay with no trouble at first (8)
I believe the answer is:
stingray
'river tay with no trouble at first' is the definition.
I can't judge whether this definition defines the answer.
'fish bite on' is the wordplay.
'fish' becomes 'ray' (ray is a kind of fish).
'bite' becomes 'sting' (synonyms).
'on' says to put letters next to each other.
'ray' after 'sting' is 'STINGRAY'.
Can you help me to learn more?
(Other definitions for stingray that I've seen before include "Fish with venomous tail" , "Marine creature with venomous tail" , "Poisonous spined fish" , "Dangerous fish" , "menace in the water" .)