Need help IDing a fish!

We have a mystery fish this year. We are in NYS, an hour and change north of the city. We have a garden pond fed by an intermittent stream/roadside ditch. Usually we have crayfish, bullfrog tadpoles, a few wee smallmouth bass and some sunnies, as well as the pond fish.

This year we had a stranger. It's about four inches long, grey with a sort of lateral stripey look, and a very blunt head with sort of barnacle-looking bumps on its forehead. Very distinctive. We are not sure whether to put him back in the pond or quarantine him. I took a full body shot OK but the closeup didn't come out. If I can figure out how to post the photo I will.

I love the Internet !!! It is a fathead minnow, a male... I'm so happy that it's a regular wild fish. Happy gardening all....

And it's at about its full adult size. I made the mistake of adding six "Golden Orfe" a couple of years ago (because my koi were being excessively bashful after a particular pond tragedy) thinking they would help snap my "real babies" out of their funk. It worked fine at first, but once the Orfe's started getting bigger, their hyperactivity and skittishness really freaked out the koi. They are now housed in my mother's new pond (she doesn't know any better! lol) and the rest of the population is not back being rather sociable and happy.

Oh ... back to the minnow. They seem to have no ill effect on the koi. They might harbor certain diseases or parasites "better" than a koi might, but I have zero evidence of such (and I have a decent sized school of those puppies in the pond) I only pray this is not the case as I would not want to begin to estimate the replacement of our 12 adult koi.

Thanks. Uh oh I did add two small somethings this year, they may have been Orfes. I'm not sure. I would like to find another Sarassa comet, we only have the one and s/he is so pretty. All the fish are chillin' for the winter now though.

PS Do you know how I add that "SOLVED" to my subject now?

Hi Lizzie! I don't think the water garden forum has a "solved" marker. Only forums like plant and insect id do.
I love your native minnow though. So beautiful! It's almost irridescent gold isn't it? I would love to see pictures of your pond and the natural stream that feeds it. I am a little starved for water garden pics right now, mine is to bed for winter also. Glad you got it id'ed!