Help- pretty sure my Betta is uprooting the plants - would a Marimo Moss Ball be better?

[RhubarbRhubarbRhubarb]

I haven't come across any info regarding Betta's digging up plants but he seems to be doing it.
He can't manage the Anubia as its so big but i wondered if the Marimo Moss balls would be better?

Can anyone recommend a good online supplier?

[EauRouge]

Have you seen him doing it? What plants are being uprooted? Moss balls would be fine with a betta. I've never got a moss ball from Plants Alive but I've had other plants from them and they've been fine.

[RhubarbRhubarbRhubarb]

Well, no not actually seen him doing it but not sure how else its happening. They are Cabomba Caroliniana and i planted them securely.
We've had them for ages and its only recently been happening.

[EauRouge]

How long are the roots and what substrate is it? Some plants can be a bugger to get them to stay put and even a fish swimming past can dislodge them.

[RhubarbRhubarbRhubarb]

The roots are pretty long, I've seen some up to 4cm.

The substrate is natural gravel like this

Maybe it is by accident. I hadnt thought of that.

[Catypillar]

Don't know about the moss thing but I've stopped my corys from digging up the plants by putting 2-4cm pebbles around the roots.