Actually just a few fish and Malaysian snails to grab uneaten food in the breeder tank, I chose it because it is shallow and the plants could use a low wattage light source, just a shoplight with two 40 watt bulbs. As you can see from the sand in the 2nd photo it doesn't get a lot of debris build up, and the inhabitants of the main tank are messy eaters.
Here are some of the fish from the 100 gal tank, not super crowded, but not sparse by any means.
Here are some of the fish from the 100 gal tank, not super crowded, but not sparse by any means.

.