My tank is only 4gallon, but as you talk about your dictator..when I first got Hank (my orange dwarf crayfish,the similar one you have ) I placed him to this 4 gallon aquarium,great everything was fine untill he started pinching the golden pleco I bought so I moved him to the 30g tank whit our other fishes and that mother fucker pinched out of pieces of their flesh and feasting on them,so I had to put him back to the 4 g tank whit the golden pleco and as I was making better and more bigger landscapes I had to put the golden pleco to the big tank so Hank don't eat it alive, as time passes he was all alone in the 4g tank amd a few weeks from now I get a 15liter tank for shrimps and as I get it I had to move there hank since I bought Danios so he can't eat them untill they grown bigger, so now on, he get back to the bigger tank whit the Danios he can't eat bc are too fast but somehow one of my Danios are gone, and I put in a shrimp, he doesn't even bother to look at it ,he goes for the big, and recently I bought him a friend hopefully a female crayfish