Ich
General Info and Prevention: Ich is a parasite which you may also found called Ick or White spot. It is pretty common in bettas but is pretty pesky and contagious to other fish. It is pretty easily treated if done quickly. You can prevent ich by adding aquarium salt to your betta’s water and one drop of Aquarisol per gallon (see the First Aid section for more on Aquarisol). Ich can also come from live food, which is why I advise novice betta keepers never to use live food. It has too many risks that outweigh the benefits.
Symptoms: Betta has white dots (looks like he was sprinkled with salt) all over his body and head, even eyes. He may be less active, may have stopped eating, fins may be clumped. he may also be darting and scratching against rocks, plants and whatever else he can find.
Treatment: Treatment will probably take about two weeks. First, if you have a filter, disconnect it. Medications will be absorbed by carbon filters, rendering them useless.
Several medications can treat ich, such as Aquarisol, Methylene Blue, and BettaMax (read more about these medications in the First Aid section). I recommend using Aquarisol first. Using your Hydor 7.5 Watt Mini-Heater (the one in the link is the one I use an recommend; please read about it in the Frequently Asked Questions section), slowly raise the temperature of the water to around 85 degrees F to speed up the life cycle of the parasite. At this temperature, the parasites become free swimming (meaning they leave the betta's body). Once they do that, the Aquarisol will kill them. Keep in mind: the parasites become free-swimming when they are sinking to the bottom of the tank to divide and create baby ich (ew.), and this free-swimming stage lasts about three days. It is within those three days that they are vulnerable to the medication, so you must treat then. Treat based on the instructed dosages every day for 10 to 14 days. It is advisable to do partial (big tank) or complete (small bowl) water changes in between treatments.
If this method doesn't work, try a different medication or a combination.
After treatment, keep an eye out for secondary infections. Your betta will be more vulnerable to other illnesses now that he has been weakened by Ich.