Hello I don’t know if these are fruit flies or nats but here a picture of what I am talking https://imgur.com/a/Gs8zZ. But also how would I take care not to get these fruit flies or nats into my fermenter during transferring ?
Is there body slightly reddish/brownish? If so…fruit fly.
Just make sure your stopper remains in place and the airlock doesn’t dry up. They shouldn’t be able to get in.
Looks like your fermenter is in a freezer, how do you think they got in?