White spots on the fish?
white spots are almost always a symptom of Ichthyophthirius multifiliis, often simply called "Ich", one of the most frequent fish diseases in aquariums. The disease is very contagious and can cause considerable losses if it is not treated!
Diagnosis: Whitish spots sized about 1 mm on the entire body and the fins. The fish scrub themselves very strongly. Infestation of the gills is also rather common, but is often not recognized. Spheric ciliates with a characteristic nucleus shaped like a 'U' or a horseshoe are visible under a microscope (please also see the pictures in the sera guide "Healthy aquarium fish", available for free as a PDF in our "Download" section!).
A particularly refractory and aggressive strain (possibly a different Ichthyophthirius species not yet known in aquariums) has been occurring in the aquarium hobby for a couple of years.
Treatment is possible with sera costa®med F, sera costapur F or sera med Professional Protazol (the exact dosage/application is described in the according instruction leaflets of the products). In case of particularly sensitive fish and/or suspecting the above mentioned "new" pathogen, you should by all means choose sera med Professional Protazol.
Treatment against Ichthyophthirius is always carried out in the main aquarium, not in a quarantine tank as to also combat parasite stages that do currently not dwell on the fish (swarmer stages or tomites and cysts lying on the bottom in which the pathogen multiplies after it has fallen off the fish). Whereas treatments based on malachite green oxalate interrupt the multiplication cycle by killing the swarmers, the active agent used in sera med Professional Protazol is effective against alle stages.
Dr. Bodo Schnell