what is the best size does it matter?

220-2 if legal in your state?
bob evans

yeah i was going to do that but the people's property im on are affraid ill catch therir cats?

Man not knowing what size fisher they can be coon size too coyote size?
I guess that a 12x12x42 would cover it?
Fisher may not go into a cage trap.
Can you set a 220 on a pole set away from the cats?
My guess the fisher is looking for a meal of feline filet?
Ask the people to keep the cats inside foe a few days.
bob

You can take fisher in any size cage trap you can catch coon in. They are not cage shy at all. You have to make sure the door is a positive closing door that will force their butt in to the cage and not open. The 10x10 Williams trap works well. Stake the trap so it can't be turned over and you will be in business. Good luck.
Dan