Some people use a growing tank with no filtration and no gravel on the bottom.
I know that when you have a tank of adult fish you need a medium for the
beneficial bacteria "biological filter" which is the gravel and the filter bag
or sponge. Do fry need a "biological filter"? Can you use a plain tank with
just water and an air stone to raise the fry, and if so, when do the fry need
the "biological filter"?
Thanks...
John Dowden
ejdowden at raleigh.ibm.com