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[Ruskull]

As already suggested, I would get him some floating plants.  I have Brazilian Moneywort in one of my Betta tanks & the Elephant Ear Doubletail loves to rest in it like a  hammock.  That particular plant can be used as a floater or it can be planted in the substrate.  It has very small, lilly pad like leaves that don't look too overbearing in smaller sized tanks.  I like it so much I plan to add some to my other Betta tanks.
 
Anubias are also good in Betta tanks. They can be attached to wood or rock & provide a shelter for the Betta to help them feel secure.  In fact my Dragonscale Plakat "Igor" hides in it all the time showing only his face.  When I move towards the tank he swims out like a hunter! 

 

[KasumiBetta]

I've had no luck at all with floating plants. I've tried both Java Fern and something else...can't remember what it's called...somethingwart. They both turned to mush in just a couple days.

 

[DreamertK]

Hornsworth became a christmas tree in my tank. Anubais is a very hardy plant that doesn't require much of anything at all. I've seen my LFS use a ton of them as a floating plant though I superglued mine to a piece of wood.