I am really surprised your Uaru (pronounced Waroo) is eating your Java Fern as that plant is not palatable to them. I currently keep 6 Uaru A's in my 125 G. My advice is to keep them in a group of six. They are a great fish! Death Angel is correct, they nibble (actually peck) on Driftwood.
The main thing is to maintain a little higher water temp. I keep mine at 82 df, but some folks I know are keeping them at 86 df. They appreciate soft water, again I keep mine at 6.8 pH and 5KH and inject CO2 - my tank is fully planted. I add about 1/4 the black water extract that is recommended on the bottle - I use Kent - and have some Fluval Peat - I like that brand because it's pelletized and easier to measure out - again about 1/4 the recommendation on package, in one of my three canister filters. There is a little tanic visable but it is not as dark as some Discus tanks I've seen. Keep in mind that some diseases are more active and volatile in more soft/acidic water, especially HTH.
My Uaru do not eat the Java Fern, the Anubias (all types), the Crypts (all types) and my Swords (again all types), they even leave my Rotala Indica alone.
I feed them a very broad diet which includes a plethora of various cichlid pellet and flake - both carni, vegi, and 50/50, Shrimp pellets, Aquadine Duraflakes 50/50 (a great food!!) and a frozen combo of Bloodworms, Krill and Brine Shrimp. They also love Romaine lettuce - don't feed them Iceberg, it's usleess nutritionally. I tack the lettuce between the two halves of my magnet algae scrubber - it works as well as the leaf clips.
I suggest visiting The Uaru Forum (http://www.uaru-forum.com
). That sight - which I am also a member - is full of info on keeping the Uaru A. and the Uaru F.
Goodluck. Maybe I'll see you at the Uaru Forum sometime soon!
Peace - dwj