They learn from each other, The Crown tail and the Blue PK have been watching the DT eating the roots of the floating plants and now they are starting to do it also.
I am in the process of trying to teach then that Trumpet snails taste great, every day I get a Trumpet snail and damage the front of the shell so it cant hide in there and the girls eat it, they are starting to eye off Trumpet snails on the glass now, the Blue PK managed to get one off the glass and eat it, Wont be long before they figure it out.