Marimo Season!

About a year ago, I ordered 2 marimo moss balls from Malaysia. They were tiny bundles of algae, strongly resembling tangled felt and I completely fell in love with them. They require very little attention, an occasional squeeze here and there, a change of water about every second week. When they are happy, they will puff oxygen bubbles from their photosynthetic activities. Perfect pets for someone who doesn't spend too much time at home. Now, one year later, I finally ordered a few more for my friends and myself. I was really surprised to see just how much the old ones have grown! (marimos grow about 5 millimeters a year.)

Bottom picture features a size comparison, the ones on the left being my 1 year olds. 

So if you are considering buying some marimo balls for yourself, here's a few tips on how to keep them healthy...

1. Change the water about every 2 weeks (between 10-14 days), depending on the size of the container. Their natural habitat is the bottom of a lake so don't use warm water, though best not put them into very cold water either. If your water is "foggy", worry not, it's mostly just tiny air bubbles that will disappear quickly. I usually wait until the milky white fog disappears so my marimos have a stable environment to go to.

NOTE: Chlorine is bad for marimos. Yet, to be honest, I've been keeping mine in tap water for a year now and they seem to be doing fine. They produce bubbles and I have never seen any sick spots on them.

2. Squeeze them into shape from time to time. I do this while waiting for the new water to de-fog. "Wild" marimos are not perfectly round, but you will not harm them with a little squeezing. Remember, there is no "core" to be crushed, marimos are, after all, tangled algae. Gently press them into shape with your fingers, but not as much as to make them denser/smaller. I like to squeeze them softly when they get too "fluffly".

NOTE: When in doubt, always think about the natural environment of a marimo. They live on the bottom of lakes, rolling about with the flow (hence the round shape). There's very little light and there's mud with other creatures, bacteria and natural waste.

3. Access to light. Marimos live under the water, but they rely on photosynthesis like other flora (therefore the green colour, duh). The important thing is to NOT use direct sunlight. Don't put them on window frames, shelves facing the window, or anywhere outside. They are only adapted to the little bit of light that penetrates through lake water and mud. A nice spot in the corner where they can chill and photosynthesize peacefully will do just fine. 

NOTE: If your marimo balls have brownish spots on them, they might be burning. However, if they turn somewhat grey, they might not be getting enough light. First aid - turn them to make sure that the "sick" part is facing the light source.

4. Nutrients. If you plan to keep your marimo in a fish tank, great! They will feed on whatever tiny particles float around and they can even help you get rid of unwanted algae growth by consuming their nutrient sources. They also absorb small amounts of nitrate, ammonia and phosphate which will benefit your fish. However, if you want to keep your marimo separately, it might be a good idea to throw in some bits of decor like sea shells, small stones or wood for the environment to be less sterile.

NOTE: When buying marimos, make sure to choose the seller carefully. Some sellers on ebay sell FAKE marimo which is a bit of plastic with java moss wrapped around it. These will NOT sink, they will fall apart easily and they will not have the typical felt texture. Also, the pricing varies, depending on the size. Tiny marimos generally cost about 1 euro, bigger can be as expensive as over 5 euro a piece (because it takes a few years to grow them).

Enjoy your algae friends and good luck!