Reef lurker

EEL

This slippery, snake-like fish often hides in crevices and can deliver a shocking surprise if provoked. Look for a three-letter answer that starts with a vowel.

"Reef lurker" points to an eel because eels are long, snake-like fish that often hide in coral reefs or rocky crevices. The clue plays on their sneaky, lurking behavior—they stay out of sight until they strike. No wordplay here, just a straightforward description of where you’d find one.