Tack nu förstår jag :o) Och hittade även varför vattnen temperaturen ska ökas till 28c...
http://www.thetropicaltank.co.uk/hdwspot.htm
In either case, increasing the temperature should kill the parasite off more quickly, because it will speed up the life cycle of the parasite, so that the free-swimming stage is reached as quickly as possible - this is the only stage affected by medications. However, increasing the temperature means there will be less oxygen dissolved in the water (some medications can lower it too), so ensure the tank is well aerated, and do not raise the temperature beyond around 28oC (82oF).
Due to the life cycle of the parasite, the whole tank must be treated, in order to kill the parasites which are not attached to fish. Therefore it is not appropriate to treat only the affected fish in a separate isolation tank.
Effective commercial remedies include Protozin by Waterlife and Maracide by Mardel Labs.
http://www.waterlife.co.uk/
PROTOZIN - protozoacide - PROTOZIN is used for the control of all protozoan and fungal infections e.g Whitespot, Fungus, Neon Tetra Disease, Velvet, Costiasis and Trichodiniasis. You will require 4 separate applications to complete the course of treatment. By gently increasing the treatment concentration over days 1, 2 and 3 the product does not burden the already stressed animals with a hard hitting formula. The final dose on day 6 is a preventative measure to try and ensure the organism does not re-occur. PROTOZIN's properties are highly effective at treating all its target organisms.
Do not use when rays or momyrids are present.
Suitable for tropical freshwater and coldwater aquaria.