I got my first tank up and going fast with an additive called tetra Bactozym that put all the good bacteria in the tank. After one day I added some tetras (black widow and glowlight). I still have all eight. I was also able to get my lfs to squeeze out one of their filters in a bag and dumped that in. The water was very murky for an hour or so but I have never had any excess ammonia or nitire. If you can get them to do that for you just make sure all the fish in the tank look tip-top first.