will show you some aquatic plants. Study a bit and maybe try to get a few with similar water/light needs but otherwise a nice variety of tall to short plants will make the tank look nice as well as give him things to 'play' with. At the same time pick plants that look nice to 'you' since it's your tank. As long as he has them and he can hide and rest on them without fin snags he's not going to care what they look like.
Be aware that pet stores tend to carry 'aquatic plants' that aren't going to survive more then a few months completely submerged in water. [A mistake I made because I bought without checking on-line and then I had to replace them]
*laughs* They can be such buggers to take photos of.