Hi

I moved your question out of antbfc's thread.
It's best to start your own thread rather than in someone else's.
I think I've seen the video you're asking about. I think it's made with 2 small dishes and some sort of spacer.
From what I remember, you take a small dish, silicone marbles (?) or some other type of spacer around the edges. You take a second small dish, turn it upside and silicone it to the spacers.
You'll want to make sure the frogs can get in and out while making sure your betta cannot get to the food.
Keep a close eye on things, not all Bettas will accept an ADF as a tank mate.
Good luck.
