Marimo's are an easy addition to your office, bedroom, or bathroom!
They prefer very low light, in nature they roll around the bottom of lakes. Keep their water cold, they like it in Switzerland!
Change water every 2 weeks. If your balls are browing add a pinch of sea salt, change the water, and reduce light. If ball is no longer spherical gently roll it around to reshape.
Pro tip: Use the old marimo water to water your plants! It's like vitamin water for them!