How big substrate is too big for ADF?

[Beckanva]

I keep reading that African Dwarf Frogs can get stuck under pebbles if they are too big, but nothing tells me what too big is. I have normal size aquarium gravel for the most part, but for decoration, I mixed in some of the glass beads like what you would find in a plant vase. They are maybe 1/4" by 1/2". Would these trap a frog, or should they be good?

 

[IsabellaRows]

He should be fine. What it means is if your frog looks like he can wedge himself in the gaps, it's too big