That sounds interesting... I've never heard of that, but I would defiantly say to separate them. Maybe float one in a plastic bag for a while...

 

Sounds like maybe the pleco does not have enough to eat... they ARE catfish, and catfish are generally opportunistic feeders. If he can catch the betta, he'll try to chomp on him.

Try providing him sinking wafers or blanched vegetables.

 

try feeding your pleco a little more often..they are omnivores...they eat meat too...fish is meat..

 

Thanks for the tips. How often should I give an algae wafer? I guess I was afraid of overfeeding.

 

depends on the size of the pleco.
Babies are always hungry and I feed my little one twice a day- large algae wafers and she still chews up my mopani wood. My older plec gets 1 large wafer alternate days with 2 wafers and twice a week they both get sliced cucumber.
They will also be happy with plenty of algae to eat.
Sometimes plecs chase other fish away from the food especially if they are hungry.
Do you have somewhere for the pleco to hide like a nice bit of wood?

 

I don't think mine is a baby. She's about the same size as my betta. I'll try one a day. I was giving her one every other day because there is some algae on the side of the tank that she doesn't get, so I figured she had enough.

There is a fake rock with holes that she likes to go in. She also makes holes in the sand under the rock sometimes.

 

I have seen a pleco chase a betta out of a cave. You can add more hiding places and a thick plant the betta can sit in instead of sleeping on the bottom where the pleco can chomp him.