Hello all. I have a small tank with a single 2 year old guppy. He is generally very healthy, but has been swimming sideways/in odd patterns, and seems to have slightly red gills for a couple of days. This has happened before, and we have used "general cure" and cooked peas with success. However, it's happened again and doesn't seem to be helping. We keep the water clean, and his water hasn't changed at all from usual. Any advice, resources or referrals would be appreciated. Thank you!