happy to hear one is doing better, Isolate the sick one(if you didn't yet).
Next cool the water abit it will slow down the progression if its fungel(76f, it wont hurt or bother the betta)
It actually sounds like a few things together to me, and not something that in the stage that aquarium salt would solve the problem..
If it was mine I would treat him for the following(which should solve most other problems if he has them)
Columnaris
•Symptoms: White spots on mouth, edges of scales and fins, Cottony Growth that eats away at the mouth, Fins rapidly disingrate, starting at the edges
Gray areas around head and gills, As the disease progresses the gray lesions may change in color to yellow/brown/red, Lesions often occur in front of the dorsal causing a “saddleback” appearance, Lethargic, Loss of appetite, Clamped, Gasping for air
•Treatment: There are 2 versions of Columnaris: chronic and acute. Chronic Columnaris can take days to progress while acute can kill within a day. It is contagious so isolate sick fish. If more than one fish shows symptoms then treat the entire tank. Perform daily 100% water change in small tanks or ¾ water change in larger tanks. Make sure to clean the gravel. Treat with Aq.Salt: add 1 tsp/gal Aquarium Salt 3 times, 12 hours apart so that you end up with 3 times the normal concentration. Do NOT raise the temperature as it thrives in temps over 85*F, however, lowering the temperature does not seem to help fight it. Combine salt treatment with Mardel’s Coppersafe, Maracyn I & II, API Erythromycin, OR API Triple Sulfa, combined with Jungle’s Fungus Eliminator (if possible).
Next cool the water abit it will slow down the progression if its fungel(76f, it wont hurt or bother the betta)
It actually sounds like a few things together to me, and not something that in the stage that aquarium salt would solve the problem..
If it was mine I would treat him for the following(which should solve most other problems if he has them)
Columnaris
•Symptoms: White spots on mouth, edges of scales and fins, Cottony Growth that eats away at the mouth, Fins rapidly disingrate, starting at the edges
Gray areas around head and gills, As the disease progresses the gray lesions may change in color to yellow/brown/red, Lesions often occur in front of the dorsal causing a “saddleback” appearance, Lethargic, Loss of appetite, Clamped, Gasping for air
•Treatment: There are 2 versions of Columnaris: chronic and acute. Chronic Columnaris can take days to progress while acute can kill within a day. It is contagious so isolate sick fish. If more than one fish shows symptoms then treat the entire tank. Perform daily 100% water change in small tanks or ¾ water change in larger tanks. Make sure to clean the gravel. Treat with Aq.Salt: add 1 tsp/gal Aquarium Salt 3 times, 12 hours apart so that you end up with 3 times the normal concentration. Do NOT raise the temperature as it thrives in temps over 85*F, however, lowering the temperature does not seem to help fight it. Combine salt treatment with Mardel’s Coppersafe, Maracyn I & II, API Erythromycin, OR API Triple Sulfa, combined with Jungle’s Fungus Eliminator (if possible).