I was wondering to fill the whole entire bottom with java moss, do you need to buy alot of bunches to do it, or does it grow throughout the entire bottom of the tank?

My understanding and experience is that Java moss needs to grow on wood and to a much lesser degree on some kinds of rocks. It will grow as a bunch that floats around but this dosen't look good in my opinion. I would choose another ground cover (most require more light than Java moss does), and have the wood that's sold for aquariums, the kind that sinks, as a place for the moss. Maybe you could half bury flatish peices of wood in a way that makes it look like it's growing as ground cover. You need to tie the moss down to the wood in the beginning with thread untill the moss begins to grow onto the wood. It's beautiful stuff but can collect debris unless you prune it regularly. Algae eating shrimp do a great job of pruning the moss as well as some fish which will pick at it but don't seem to be able to pull the moss from the wood after it has grown onto and set it's root into the wood. You can also clean the moss with a gravel cleaning siphon. It wont hurt thr moss. Once it has established itself it's hard to tear it up. Good luck.

Wow. I've never had my java moss grow onto the gravel. What kind of lighting and what kind of gravel are you using gumbii? I've had it grow on rocks that have a rough surface but not the gravel I'm using. Are you using CO2?

I'm trying to grow a type of fine grass (I forget the name) which needs a lot of light. I'm getting it to spread slowly after breaking up the origonal clump and spreading it out around the forground of the tank. I have a medium sized rounded pebble kind of substraight with peices about 3-4 mm in average size and it doesen't hold the roots so well. Some of my fish have been pulling it up a little. I think at some point I'll have enough grass growing that it will spread exponentially and create a root network that is harder for the fish to pull out and then it should look really nice. I don't use CO2 but I do have about 3 watts per gallon in my 100 gal tank. I have the Java ferns growing nicely with the Java moss on the various peices of wood I have. I think it's best to pull the excess moss from the wood periodically. Doing this doesen't seem to actually tear it from the wood, it just makes it look better. When the moss is too long it gets filled with junk and doesen't look good in my opinion