my fish got what i thought was anchor worms and then 1 died just after i added a new plant!i dont know any like amonia levels or anything!

You havent really given us much to go by.
Could you fill in as much as you can from the box above and take along a sample of your tank water to a pet store and ask them to test it for ammonia, nitrites, nitrates and ph for you.

How is the fish?

he died

I am sorry to hear that.