I have 5 Indo dat ranging from 4-9 inches what can I do to get the swimming around. Now that the have put on some size since we got them they just lay around the tank like a school of dead fish.Been thinking about selling some to see if that would get the others out more but have no clue what ones to sell.The 4inch one runs the tank and is out in the front most of the time and so is one of the 7 inch guys the 9 inch comes out some but the other 2 seems to hide if they see ppl even with just the moon lights on.