If your tropical fish aquarium have been affected by the white spot disease, you should take corrective action quickly to avoid that the fish suffer.
To fight the disease successfully, you should know which is the causing of the illness and when it is the best time to attack it.
The white spot disease, is caused by a family of ciliated protozoa (Ichthyophthirius).
The disease is also known as Ich or ick.
The protozoan has oval or pear-shape and moves through some short hair called cilia.
The biological cycle has two phases: a free phase and an infecting phase.
It is during the infecting phase when the disease manifests itself as white spots.
In this stage the protozoan attaches itself to the fish, penetrates the skin and feeds from the intercellular fluid.
The spots appear as a reaction of the immune system of fish that tries to stop the infection.
While the parasite is encysted in the skin of the fish, it is called trophont.
Once the trophont stored enough reserves, it leaves the fish.
It descends to the substrate, covering itself with a protective shell and begins to reproduce by cellular division.
It can produce up to 2000 parasites.
Once the reproduction finished, the new parasites emerge from the shell.
In this free phase, they are denominated theronts.
If the theront do not find a new fish to parasitize in 24 to 36 hours, its reserves will be drained and die.
The medications to attack the disease, are only effective against the theronts.