You made the right decision. If there is one thing I have learned its that there is ALWAYS going to be another fish
. Focus on the guys you have right now and getting Carlisle healthy.
The hardest thing in keeping bettas is resisting temptation. Believe me, I know from experience. I refuse to even look at the Bettas in pet stores any more because I was coming home with a new fish almost weekly it seemed. Finally I had to realize that I can't keep getting more fish. Now I've set a limit for myself and have to work hard not to go past that limit.
Now I have the exact opposite problem. When I'm looking at a fish I can never make a decision because now I'm thinking "what if something better comes along" LOL