Fin rot on betta?

Hi, I've had Luigi for a year now, and I noticed that his fins are torn up. I'm pretty worried, and I have no experience whatsoever in treating fish diseases, since Luigi is my first betta. He's in a filtered and heated 5 gal tank, and the test strips show that everything is optimal. I do 25% water changes every week, and clean the gravel every 2 weeks. I'm going to go out and buy the master test kit, so I can have more accurate results. I've posted a few pics of him, what should I do?

Yes, please get your water parameters for us. You should normally do 75% water change each week along with vacuuming the substrate and cleaning the tank. For now, you need to do daily water changes of 75% and add 1 tablespoon of aquarium salt per gallon of water. After initial dose, add 3/4 tablespoon per gallon with each daily water change of 75%. Be sure to dissolve salt first or it can burn the fish. Get back to us with parameters.

Thanks so much! Also, I have a nerite snail and some lobelia cardinalis in my tank. Will the aquarium salt harm them? Or should I move Luigi into a smaller 3 gal tank I have?

You better move him then. My snails don’t do well with salt.

Will do! These are my water parameters:
Ammonia: ~0 ppm
pH: ~8.2
Nitrite: ~0 ppm
Nitrate: ~0-5 ppm

Ouch, my pH is higher than it shows on the test strips. I'm going to acclimate Luigi in a quarantine tank and try to see why my pH is so high.