They are in the 540, check out my other you tube videos. Some of the dats are larger than an open hand. I have had them for 3 years and got most of them when they were 2in. dats are slow growers compared to other monsters. I accumulated 9 but lost 4 along the way. The more you put together the less they hide and more active they are. They fight amongst each other with 3 or less. I like to keep datnoids in groups of 5 or more- thats when they become really active like little "water puppies" greeting you at the tank and such. Get 3 more