Hi! When I set up my 2 gallon planted betta tank I bought two java ferns to put inside. They didn't look so good, with lots of brown spots and patches, but I figured they'd be fine. About a month or two later, I've noticed a new crop of baby ferns growing in the back, which look very healthy. The problem is, the original fern's leaves are turning brown and look wilted compared to the new ones. What should I do about the old leaves?