

What the title said, Jasper, my betta was very healthy before we decided to add shrimp, at first I went with some very young small group of 4 neocaridinas, however they all went missing and it was assumed Jasper or my mystery snail had eaten them
So I went searching and heard that some bigger species of shrimp like, ghost shrimp not only work well with bettas but are usually sold at a bigger size
My brother found a place that sold these so called "Ghost Shrimp" and he got 4 of them as a gift for me 2 of them jumped out of the aquarium, I accidentally left one of my lids off, but then today we had the unfortunate surprise of fiding Jasper's fins in a very poor state, at first I assumed fin rot, however I noticed the shrimp were hunting him down.
I searched a bit and learned of "prawn/whiskers" shirmp species and realized I was sold such stupid creatures
I am mad, I am worried
We got rid of them, gave them back to the store, however I now need help on how to heal his fins, any tips?
19g/72L tank
1 Betta
1 Mystery Snail
4 Albino cories (We'll add 2 more once Jasper's healthy, worried 2 more fish will stress him more)