Betta Fish: what’s up with her tail/ slime coat coming off

so she has holes in her tail and if you look closely at the top of her head there is a slimy substance. i had to move her to a new tank not by choice. i added tannins and just added aquarium salt into the filter. is there any more i can do? i’m going to be buying more plants for her soon so she’ll feel better. and since it’s a fish in cycle i am monitoring her water closely.