Interesting ! is there a reason to not stick the cube to the glass of the tank instead ?
Reason I ask is because I noticed my few wilds I have do not eat them off the glass but wait for them to fall off (loose) when the other (domestic) fish start pecking on it. I always wondered if wilds prefer to eat loose worms ones over a cube on a class.
Can't wait to see some pics of all the 4 wilds together