I have never used commercial bacteria products, I just use sludge from an established filter dumped into the new one, even if you have no tanks going yourself you can usually find someone who does, I have hit up a local junior high and a public library before. Doing that and then adding a few fish (or one larger one) at a time means you can start adding your keeper fish on the second day. You could right away but I like double checking everything including heater settings before picking up the fish. Add a couple fish everyfew days until you are at the stocking level you want. Just avoid the really delicate ones like glass cats until the tank has been running a couple weeks.