I have 2 2-inch common goldfish with (mild) fungal and possible parasitic diseases in a 29 gallon tank. If you want the whole story of how I got them and what I have planned for them, it's in my post history. Yesterday, I got my Sulfaplex in the mail and decided to do the first dose. You can barely see the fungal spots on their bodies, but their tank mates had it pretty bad so I figured I should treat them before they got worse. I did the correct dosage (2-3 measures per 10 gallons; I did about 7 for my 29 gallon tank) after a 30% water change. Now the only reason I'm even writing this is because up until this morning my remaining 2 goldfish have been inseparable, swimming together and playing in the bubbles from their air stone. I woke up today and one of them was doing its laps like normal, except maybe a little faster than normal. The other one is hanging around near the top (about 3 inches below the surface, not gasping or anything just kind of hanging out). I look and every now and then they are together in that spot, hanging around. Should I be worried? Do a water change? I've never owned goldies before so I don't really know what "normal" behavior is. If this was my betta I wouldn't be worried. We also had a pretty terrible thunderstorm all night last night, which I feel is worth mentioning. The thunder was so loud the walls shook, and my tank is touching the walls. The rain and thunder continued this morning. Is it possible they could be shaken up from the storm, and the timing is just coincidental? Thank you for taking the time to read this!