As fishfinder has said the artemia are what you are looking for to feed them with. I have kind of stayed out of the picture here as I find that she is offering you excellent advice and doing a fine job and I really do think that too many people giving you advice can confuse you. I would like also for you to try to take the time to read those posts that are at the start of the Betta Forum as I do think that if you do it will help you to see what another betta expert who has done this several times has to say.

I wish you well and think you have a great start. Please do not think that any questions or comments you are making are out of line or not needed. This is what we do here, help each other. If you need help that cannot be found from one of us that is what the big forum is about. There are a lot of us because our collective knowledge is here to help. That is the idea and we want you to ask any questions you may have.

The welfare of the fish and the ability to help those who care for them is our concern and our purpose. So please do not think you are bothering anyone.

Rose