it grew big in my 55 when i had my tiger in there, i still have it. i got a clump of it, and i cut it up into 1/2" pieces, and spread it around on a few pots and used a hair net to hold it in place and its thriving. the oscars i have dont care about it. occasionally i would find a small bit that was detatched and stuck on the intake of my filter, id just take it out. all in all java moss is is very very easy, but i do have two 40w 4foot aquarium/plant bulbs in the light fixture. the stuff is great, now that i dont have the oscar in there its surprizing how far it can go without a waterchange. between the javamoss and japanese mossball, its a fair bit of vegetation, and its really helped improve the quality of my water imo. so yeah, put it in there, at worst the fish will tear it to pieces, which u can take and hairnet them to something and they will grow just the same lol. go for it!