[VinceIII]

I have three marimo balls in a 5.5 gallon tank that I set up six days ago. Today I noticed the beginning of what appears to be a white gelatinous/fuzzy substance forming on the tips. It's very light at this point. Other than this substance, they look green and healthy. I don't see the substance anywhere else in the tank. Do you have any idea what the substance might be?

I wonder if they're getting too much light. The light is an 8000K full-spectrum fluorescent (it's the only 15-inch T8 aquarium bulb I've found), and it has been on for about 12 hours a day the past few days.

I might just take them out permanently, because I've grown away from how they look in the tank. I'd just like to know what the substance is and if it's a threat to my betta or anubias. Thanks!

 

[AquaAurora]

Marimo balls: care & info | Aquariadise

Marimo turning white / lighter means that it is probably receiving too much light. If the Marimo also seems a bit slimy or if its texture seems otherwise unusual, you may be dealing with a hostile type of algae growing around it. These algae choke the slow-growing Marimo, so it’s best to carefully wash them off or remove them with tweezers.

I'd not recommend having an aquarium light on more than 10 hours at the most, I usually do 7-7.5 hours of lights on. Keeping marimo in the shade of other plants/hardscape is advised in a medium or high light tank.
The white stuff won't hurt your betta or anubias, its essentially 'burnt' marimo tips. Clean them then put the marimo in the fridge in a cup with some tank water for a week and they should be fine. Or just rinse them off and sell 'em now if you don't want them anymore.

 

[VinceIII]

Thanks, AquaAurora!