I love this fern. It’s very hardy, and it looks like yours is reproducing. Windeluv typically doesn’t like having its rhizome buried in the substrate, so it could have some rot. These plants frequently threw off baby plants if they are challenged like that. A broken leaf can reproduce.
if you remove the tip of one of the leaves with roots, you can super glue it to a rock. Next thing you know, new plant for your tank.