vvvinegar

I've heard of pouring semi-warm tap water into plastic bags and letting them float in the tank to preserve heat- If there's time, you could also possibly change some of the water to reduce any toxins that might be potentially harmful to your fish.

So I've noticed some white spots on my fish's lower fins (I hope y'all can see them through the photos). My fish, a betta, had a brush with fin rot quite recently although due to a variety of perscriptions, he seems better now. I don't want to sound too paranoid, but I was wondering whether the white spots could be fin rot or ich although they could just simply be the natural markings on my fish. By the way here are some close up pictures that took forever to take because he won't hold still:

The Quarydoras (since "quartet" alludes to a group of 4) Or The Four Horsemen ¯\_(ツ)_/¯