Original sentence
Moray eels hunt by night and hide in coral crevices by day.
Grammar explanation
- The sentence is a correct simple sentence with two actions connected by and.
- Using parallel structure helps: hunt by night and hide in coral crevices by day.
- No extra punctuation is needed; a period is enough at the end.
Corrected (unchanged) sentence
Moray eels hunt by night and hide in coral crevices by day.