Clamp For Flash Or Small Camera Any Help With Sick Goldfish With Red Fins, Clamping, Flashing, White Spot...?

Any help with sick goldfish with red fins, clamping, flashing, white spot...? - clamp for flash or small camera

I have 60 liters with 3 medium and large goldfish, tank has been running for over 2 years with filter plate and set a great cycle of the rule, and so on.
He lost only one fish (rear), which I found was due to nitrate poisoning because he had been absent for several weeks, and when I returned to levels of nitrates through the roof with a lot of green algae. Fish was quickly abandoned, and shriveled and died, although it is clean taken to a hospital tank, etc. .. Then I switched to water about 80% for 2 goldfish, the common and all seemed well for a few weeks.
Last week I bought another big common goldfish, to replace the loss. Then I realized that I had lost the magnitude redder. Second, silver fish, but was usually very nervous, "intermittent" a little. At first I thought it was because of the new fish "Daisy" to pursue both at the tank at all times, but today, the Big Red with red stripes on the wings and tail, and was looking about. Have you noticed one or two white spots on fish, so he told the Petstore andput their own brand of white spot treatment and aquarium salt to 1% ... Still not convinced, or exactly why the fish are sick, but because it is literally only one or two white spots on each, both in the dorsal fin and tail. It could be parasites, or I thought maybe a bacterial infection of the loss of scale? At first thought the damage was through the fish they pursue the causes new "Daisy". Oh, also changed 20% water before the treatment of white patches that contain nitrates have crept back up to 80 ppm with an algal good start again ... Ammonia and nitrite, all negative, PH, KH, etc, everything seems good ... Has anyone any advice?