I just finished up my 60 gallon grow out. 48x12x23 Its got an O BGK and Raphael cat that are all about 3 inches long with the cat being the biggest. The O and BGK do good together. Both eat worms out of my hand at the same time before after lights out. The O is very active during the day and hangs out in the plants and DW at night. The Knife is the opposite rarely seen with the lights on. I added a red led night light and got some good looks of the knife and cat cashing ghost shrimp. Knowing the growth rate of these 3 i plan on having something thats at least 18-24 inches wide with the yr. 120 gallons + good louck