We all know bettas get sick like we do. Here is a list of Betta Diseases and their symptoms and treatments. For most disease, adding a little aq. or Epson salt and clean water can be the solution.
Symptoms - abnormal sized eye with a white lens.
Treatment - Erythromycin for ten days.
Symptoms - bloating, big eyes, and greyish coloring. In more severe cases, pineconing
Treatment - Very fatal if not treated. Usually a symptom, so it depends.
Symptoms - white fuzzy spots in gills and other places
Treatment - Add Aq. salt and medicine, clean tank and stop carbon filters
Symptoms - Velvet like patches, weight loss
Treatment - BettaZing(also good for clamped fins) or BettaMax
Symptoms - black or red edges on fins
Treatment clean water!
Symptoms - white spots on body
Treatment - aq. salt and clena water unless severe.
Swim Bladder Disease
Symptoms - crooked swimming, sideways
Symptoms - refusal to eat, red streaks on body, very FATAL
Treatment - Treat right away! check water parameters (pH should be 6.5 - 7.2 and ammonia should be 0) fix them and give the fishy medicated food. It may be too late :(
Symptoms - Duller in color, clamped or ragged fins, pop eye, can get to humans!
Treatment - None. Once a fish has it, remove it from the tank and in a small cup. :(
Hopefully this helps betta owners! Be free to add more diseases to the list. Always keep a bag of Aq. Salt and watch you fish! :D