Can Bettas have tumbled lava stone in their tank?

I am getting different answers on this, so I thought I'd ask some experts. Is it okay to have lava rock in your aquarium if you have bettas? I am doing a fishless cycle right now, and I bought some anubias nana to attach to some of the smooth, large river rock. The plant is not attaching very well, so a few people told me that some tumbled lava rock might help, but I was worried about then getting a betta later due to the damage it might cause the fins. Any suggestions?
Here is what I'm wondering about (haven't purchased any yet).

 

Not an expert on bettas, but tumbled lava rock looks really smooth, I can't imagine how anything could get fin damage on it. Especially since you're not going to cover all the bottom with it, but only use it as a plant anchor. I think it's the unprocessed lava rock that is a danger to bettas.

 

Thanks so much for your help!

 

I would not worry, its pretty smooth. Go for it!

If it was not tumbled I would pass but this has been smoothed down.

 

Thanks much for the advice!

 

Bettas typically hang out in the upper levels of the tank. Thus, they are not likely to be affected by your substrate type.. However, be sure you do not have any bottom dwellers that might get stuck in the crevices.