r/Marimo

I think so!

As I’ve mentioned in other threads, I highly recommend buying the biggest Marimo you can find. I’ve seen so many cases where people buy nano-sized ones, expect them to grow quickly like tulips or crocuses, and then get discouraged by how incredibly slow they actually grow. In the worst-case scenarios, they just lose interest and end up neglecting them (though, to be fair, taking care of giant Marimos is no walk in the park either! 😅).

The one in the photo was about 7 cm (2.75 inches) when I bought it back in 2019, and now in 2026, it has grown to around 8 cm (3.15 inches). Compared to the tiny ones, it definitely makes a much better eye-catcher in the tank!

hello everybody this is my first post here, i have 4 marimos 1 has split which i have tied up with a rubber band to try to help it keep its shape, some backstory i bought these about 2 1/2 years ago for my bettas fish tank, he died a few months back and i moved them from the tank to this glass vase and im not sure im taking care of them properly due to the one falling apart . can anyone please give me tips and advice on how to properly care for my marimos! also in the first pics there is a lot of like debris in my vase and i just cleaned their water a week ago does anyone know what that is from? thank you!

I was about to change the water and I noticed that they were like this, are they dying? What's the white spot on the one on the left?

Pic of Mo the Mossball (my art) for attention.

Like the title says, I would love to know where you buy your balls! I assume somewhere online, or in aquatic shops, but is there anything like a community swap or discord server where you could get them directly from other hobbyists?

Thanks in advance!

Last year, the water from my marimo tank evapoted because i accidentally left it direct sunlight. So i placed it in the refrigerator for several months to recuperate. With no hope, this year I brought it out of the refrigerator for several months at room temperature. Then recently, voila! Green spots! Is this normal?? Does it mean, it's still alive??? Has anyone experienced this??

it's been a rough year for these guys. I'm sorry for the graphic images. I never thought i'd be one to end up shoving images of my neglected little creatures into a feed of beautiful bright green glowing orbs.

I'VE OFFICIALLY JOINED THE LEAGUE OF EVIL MARIMO NEGLECTORS.

Let me know if any other visuals or info would be helpful. As you can see they are somewhat broken and dull. No bad smell despite lack of water changes.

Also, thoughts on keeping a penny with them? Harmless or not?

I have thrifted 4 or 5 separately now so I have to stop picking them up but I love these ruffled edge fishbowls! The lid to a glass teapot fits perfectly, so I ordered some extra replacements so I can have lids on them all!

The first two pictures I wanted to include because it was after 5-7 days of being in a bowl with a lid! It still gets all this buildup of white dust like particles. I don't notice it until I swirl the bowl and it looks like a snow globe.

I just pour cold tap water into the bowl, watch the marimo tumble around a bit, pour some water out, and repeat a few times. If the bowl feels slimy, I'll wipe it with my hands and just water. Every few months I'll give them a gentle squeeze and roll them between my hands. And take a little sniff.

Eventually I want to move them back to the 10 gallon tank I bought for them, it's just been easier to keep them in a bowl by the sink at the moment.

Hi! I'm trying to build a marimo carousel with my moss balls moving around. I bought two little 10W pumps, but I seem to be too dumb to put them properly in the aquarium.

My issue is that no matter where I put the pumps, the marimos are only staying in one place, not moving around.

The aquarium is roughly 20x20cm big and holds about 10-ish litres of water, if that's important.

Can anybody help?

I started 5 years ago with just three, but my collection has grown!

Have had my marimo moss balls for a handful of years. They used to sit in a little cup but a few days ago I added a little water pump to help them roll around. I noticed this light gray/brown film on top of the larger ones especially. What are they and how do I fix it and make them happy again? Thank you

Hey! I've had these moss balls for a while now. I bought them on a whim without researching proper care (yes, shame on me), but recently I've been trying a lot to do better.

I bought a small 20L aquarium and put some sand and stones in. Also these decorations (a Schleich platypus figurine and this 3D printed skeleton thingy). The aquarium came in a set with a lamp and this filter/pump thing you can see in the back. I started changing out half the water biweekly (with cold water) too. Ever since I did that, my moss balls grew approximately twice in size, the small one almost tripled.

Now it is summer and it's super hot where I live. The temperature is about 35-40°C in the day and around 20-25ºC in the night right now. I started doing weekly water changes (half the water) and topping it up when needed. I also add ice cubes once or twice a day to keep everything cool. Even though I am doing all that, algae still keeps growing on the ground and up on the sides.

The aquarium is set up on a windowsill, where direct sunlight hits from around 8-10:30am. I have foils on my window to help reduce the heat a little, but might that be the reason for the algae?

I don't really care for how it looks, since I kinda even like the overgrown mossy look, but is it dangerous to the moss balls?

I also wanted to ask if my moss ball care is good or if there is something I should change? I was thinking about changing out the water pump since the moss balls are so aerated they just float around on top of the water. But that shouldn't be dangerous to them, right?

Any help and tips are really appreciated <3