They eat off the glass but reluctantly and therefore not as much .
I leave 2 cubes on glass and 20 minutes later they have been nibbled on but not devoured .
They ate the whole cube in 3-4 minutes from my hand !
It is the first time I tried ..I just figured Hans feeds his beefheart so they weren't hip to the worm yet ?
As soon as they attacked it dawned on me he/his staff could still have been hand feeding frozen beef heart and the fish had no clue !
No I can take 4 minutes feed them a whole cube and leave 2 on the glass and go to work knowing they will be more interested .