I am at a loss as to why the fish is diagnosed with gill worms, which is not a common malady, and the only described symptoms are red, inflamed gills and some discharge.
I am with Dark Entity:
Start with water quality: What are the stats on the water? Always, no matter, what start with water changes. Even if the stats (ammonia, nitrite, nitrate) are fine, the bacteria, fungus, parasite, whatever load will be reduced by water changes and give the fish a chance of recovery on its own.
Get a correct or reasonable diagnosis before throwing meds in the tank.
Are there other fish in the tank? What size is the tank? How long has the fish been in the tank? Is it filtered or not? what is the water change regimen? Are there other fish with a problem in the house? Can you get a good clear pict of the fish? Are there small hairy things on the gills?
I am not familiar with any desease with black dots. (Not to say there is not one; I have not dealt with all deseases. Thank God!) Dark Entity may be correct, but it doesn't sound like she is sure. Gather this information and if no one responds to the black spots w/more certainty, post in the emergency section. Or post now, and we will work together.
For now do frequent water changes and add salt at about 1 tsp per 2.5 usg. This assumes that the fish is alone in a small hospital tank.
The gills could very easily be from ammonia burn or from bacterial infection stemming from water quality.
Check the Betta care and the Betta health sections on this site
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