Here is a clear and correct version of the sentence, suitable for a 6-year-old:
- Original: After night hunt, moray eels hide in coral crevices for the day.
- Corrected: After a night hunt, moray eels hide in coral crevices during the day.
Notes:
- Use "a night hunt" to show there was one hunt at night.
- Use "during the day" instead of "for the day" to describe when they hide.
- Moray eels is the plural subject; you can say "moray eels" or made singular with "a moray eel" if you want to refer to one eel.