Very cool fish, I have a group of 4 with 1 male, which I had to remove because they kept breeding and bullied the others. Currently the male and the largest female are almost 4" and growing, I believe they can get up to 6+". I have the 3 females with a group of 5 yellow labridens in a 55 gallon, but they are starting to outgrow the tank. I'm planing on puting the bartonis and the labridens in a 125 some time in the next couple months and I believe they will be fine for quite a while. Hope this helps.