The best thing you can do is make sure the fish are kept at the correct temperature for the species, about 24-26C for most tropical fishes. Then treat the fish with an appropriate whitespot remedy. Continue treating the tank for about a week after the spots have disappeared.
The whitespot parasite has 3 stages to its lifecycle.
1) the white spots on the fish
2) 2) the spots fall off the fish and multiply in the gravel
3) 3) the cysts in the gravel rupture open releasing thousands of new parasites to re-infect the fish.
The parasite can only be killed during the 3rd stage when they are free swimming and before they attach to a fish.
You can raise the water temperature, (maximum temp is about 30C), increasing it speeds up the parasite’s lifecycle. This causes it to develop quicker and die off sooner. However, the temp should only be raised after the medication has been added to the tank. If you turn the temp up and don't have medication in the water then the disease organisms grow faster and spread more rapidly, causing more damage to the fish.
Increase aeration/ surface turbulence to maximise the oxygen levels in the tank. Medications and high temperatures reduce the oxygen carrying capacity of the water, so the more surface turbulence the higher the oxygen levels will be.
Do a partial (30-50%) water change and gravel clean before treating the tank to reduce the amount of gunk in the gravel and this will also lower the pathogen count in the water. This allows the medication to work more effectively. You can also clean the filter out before treating but make sure you only wash the filter materials in a bucket of tank water.
To work out the volume of water in the tank
measure Length x Width x Height in cm
divide by 1000
equals volume in litres
When measuring the height, measure from the top of the gravel to the top of the water level. If you have big rocks or driftwood in the tank, remove them before measuring the height.
Remove carbon from the filter before treating otherwise it will absorb the medication out of the water.
