I bought my originals around 2-3 inches(5 of them) and bought the other 4 when they were around 4 inches. The biggest one was the exeption, he's grown since I bought him but he was much larger than the rest when I got him. They love my tank so far. They especially love the driftwood, they're favorite place to hang. I've had my originals over 3 months, the other 4 for about 2 months. They'll soon have 180 gallons to play around in. My rhom will love this tank, lots of hiding places and room to swim.