What about it made you think it was a fisher and not a mink?
Fishers are around, but are extremely rare.
The location that you’re describing would make me think it is most likely a mink. Mink are usually found near water such as streams, lakes and in this case a ditch. Fishers are forest dwelling animals that climb trees.
Mink are about 2.5 pounds and are long and slender with a slender tail. Fishers are much larger and weigh 12-13 pounds. They also have somewhat long bodies but a very bushy tail.
Thanks for your wildlife sighting. Let me know if you have any questions.
-Naturalist Denise Wolfe