I’m trying this now. Have 2 purples QT’d together and 3 yellows in a different QT tank. Thinking hard about a Gem because I’ll never have a better shot than adding them all together and I have an offer to get one for $350 but I’m scared lol. The purples are 1.5 inches the yellows are slightly bigger but not a ton maybe 2.5 for the biggest one? They are separated by egg crate to get used to each other while in QT. My DT is 220 gallons 6 ft. I’m hopeful and will try mirrors/night introduction/no lights/ any tips I can find and am willing to give up and sell some if the fish get to aggressive or it doesn’t go well.