I have 11 divided between my three ten gal tanks. I love them .they are easy to care for, grow in low light, are a lovely shade of green. I just roll them once every week or two so that eventually all sides get exposed to the light and you don't get a dead spot on them. when I do a water change I just lightly squeeze them in the old tank water to clean them then gently roll them in my hand like rolling a meatball and put them back in the tank. Any live plants help the water and use fertilizer that the fish produce. The shrimp and fish like them as well because they catch little bits of fish food that the fish and shrimp clean off as well as my cory cat fish. They sit on the gravel so you don't have to plant them and you can rearrange your tank to you hearts desire. They grow very very slowly. Easy easy plant. Alison
I have heard they can help with algae but I have never used them, so I'm not sure that is true.
Moss balls aren't actually a moss, but an Algae. They grow round from rolling down the rivers current in their natural habitat. They will outcompete some other types of algae for nutrients, so in a sense they do help fend off nuisance algae to some extent, but they won't be a magic fix for keeping algae down. They are great for catching particles, and shrimp do indeed love them as they can house all sorts of micro-organisms that are too small for the human eye to see, that shrimp and other creatures will feed on.