well, tank may be at capacity now with all those small goldfish, but i bet its a temp home.
a bare bottom tank is actually really good for water changes. just keep up with those and you should be able to keep those fish growing for quite some time, until, of course, the fish just naturally get too big for the tank!
and again, i'll say what i said on bigfishkeeper's other thread. fish look happy, healthy, and well-fed.
but i guess that will come under fire too from those act as their own keyboard judge and jury...