Hi everybody. I recently built myself a small DIY Kreisel Tank and put three H.Reidi fry in it as a test. They have been in there for just over three weeks now and have grown to about 2cm in length. Two of the fry seem to orient themselves to the "substrate" (bottom of the tank) and scavenge for food at the bottom all the time while the third still hangs in the column and just goes with the flow. How will I know when they are ready to be transferred to a nursery tank please?