That totally looks like some type of mite. You said you were looking around to see what's in there... was this from a gill scraping that you did, or just in the aquarium? Many mites are scavengers. Unless these were actually ON your fish, it's likely they are harmless.
If you're looking to see if there are gill flukes, you have to actually swab the gill and look at that under the scope. You can't use anything you find in the water to figure out if it's flukes or not.
I got that sample from mucus that floated to the top. After a water change, my Discus usually has a lot of mucus coming off their gills. I tracked one, and grapped it as soon as it reached the top. I found 2 of those things in there, still alive.