I have been raising Bettas for 20 years, and have written a series of articles for EzineArticles.
Here is my most recent one on Ich (Ichthyophthirius)
Here is a synopsis ...
"A young protozoan ich notices a betta (food supply) and bores into its skin. It begins to feed, until it reaches a large size, causing a small white spot to appear on the skin or fin. When you see the white spot, that is a sign that the bacteria is in a feeding stage.
When it becomes fully grown, it covers itself in an impenetrable cyst, and jettisons from the betta's body, where it drifts along the tank's currents until it adheres itself to a plant, a bit of gravel or a rock. The tomant stage, inside the cyst, divides again and again, producing approximately one thousand offspring.
When these thousand or so bacteria become too big for their protective cyst, they break out to find more fish to feed on, and it is only at this stage in the ich life cycle where they are susceptible to chemicals.
Formalin or copper sulfate needs to be kept at high levels in the aquarium for an extended period of time to be available when the cysts hatch. The tank temperature should also be raised slightly to shorten the bacterium's development time and give a much needed boost to your betta's immune system."
If you do not already have a betta care book
, I recommend getting one, either an e-book or hard copy, and keep it handy.
Bettas get diseases much more readily than other fish, and need to be treated properly right away.
I hope that helps.