In my opinion, actually there are no fake or real marimo. It just depend on the conditions. But there are 2 location where  marimo spawn either from German or Japan Hokaido. Beside, the two located marimo's condition will be different. A healthy marimo will have fresh green color and round shaped.

I would say, there is real and fake Marimo in market..... Some seller like to cheat people saying their Marimo is from Japan..... so that people will buy from them, but end up their marimo doesnt last long n gets brown easily.... so these are the lousy quality marimo n we call them as 'fake' as thy r not from Japan. A japan marimo, which people used to say the "real" marimo will instead stay green colour after even a long time...... unless the owner neglect them larrrr......

So, if want to get real Marimo, better buy from trustable seller, our big Marimo boss Leeyung...... guess u can view around his good feedbacks from first page of this thread here.....

P.S: Try to avoid some seller as in post #2680.... His successful threadlist are just too fake.... no offense, just that Sharing is Caring!