Help! Dying Marimo!

My axolotl tank is fairly new, a little less than 2 months running. I completed my nitrogen cycle, woohoo, and currently have two axolotls living in it with some Anubia Nana, Java Fern, Amazon Swords, and two Marimo balls. The tank is 26 gallons and has a dim light that I leave on during the day. I have been feeding my 2 juvenile axolotls blackworms since I got them, and soon realized that escaped blackworms had made a home in my Marimos. I took one out and proceeded to rinse it out with some tank water to get the worms out. Once I started, the entire ball fell to pieces, looking as though it was rotting from the inside out. A few days later I did the same with the second ball and it too fell to pieces! One Marimo was fairly new, the other was over 2 years old and was kept with both my bettas. Ive had to remove brown spots before and re-roll my older Marimo once or twice, but it always thrived before.

So here is my question. Is it possible that the blackworms had somehow killed my Marimos by burrowing inside them? I really like the aesthetic features of Marimo, and I would like to keep them if possible. My water parameters are perfect. I check them bi-weekly with the Freshwater Master kit.

I'd like to add that all my other plants seem to be thriving, except one group of Anubia nana are a little on the yellowish side. The other plants a green and growing well.

Any ideas?

I would buy more they are sold almost every where and not to expensive. But they say if they are rolled to tight they can rot from the inside out. Plus if they brown or start to rot stick in cool salt bath . When they brown they say water temp to high or indirect light usually is the problem. You dont need cycled tank for marimo's they can grow in a cup. Just change water every few days. Hope this helps my marimo i have had just as long as you. Started in my betta tank too. I remember reading some of this stuff when i first got them.

If you saw worms in it. I would think it was the worms too. But salt should kill the worms in the balls.

Ok I will definitely try the salt bath. Thanks