This is a hypothetical question! My tank (divided 10 gallon, heated and with 2 sponge filters) is still cycling, I don't have any fish yet. However, I was at the pet store and noticed almost all of the bettas have some degree of fin rot going on (or other problems, which I would try to avoid as I don't have much experience treating fish yet). If I found two fish with relatively mild cases of fin rot, would it be safe to keep them in the divided tank or should I quarantine them? The divider is mesh and allows a moderate amount of water flow between the sides. Either way I would keep the water pristine, and I have aquarium salt on hand if it gets worse. Another possible situation would be getting one without fin rot and one with. Would these be safe together, since the fin rot itself isn't really contagious but rather opportunistic? Thanks!