as someone that also has some aquaristics experience, i can say to you its absolutely unclear if its mites or something harmless.
In aquaristics, springtails are known to cause no issues, they walk around on the glass above water surface or walk around on the water surface, and eat biofilms.
a good way to tell is if the body of these things is hard or soft. Parasites, like parasitic mites, have a hard body and you can clearly feel one if you have it between your fingers. The harmless ones are so soft, you cannot even really feel them, between your fingers they just turn into a black smudge.
are the little bugs walking on the water surface, or are they drowned at the bottom of the water bowl? Parasites typically dont do the jesus-like waterwalking thing. But snakes often try to treat themselves by drowning mites in the water bowl.