When someone says they have better fish to fry it means they have more important things to do.
To have something more interesting things to do.
- To have more important things to deal with.
1. I didn’t call them back because I had better fish to fry.
2. I refuse to waste any more time trying reach an agreement with you, I have better fish to fry.
3.Celebrities have better fish to fry than to sit around giving interviews.
4. I have better fish to fry than to take care of your every time you get drunk.
at it, diligent, employed, engaged, having a full plate, having enough on one’s plate, having many irons in the fire, in a meeting, in conference, in the field, industrious, on assignment, occupied, on duty, on the go, overloaded, persevering, slaving, swamped, tied up, up to one’s ears