Coming up on 17 weeks post hatch this Saturday. I still have 8 cuttles. They are feeding on frozen saltwater "grass" shrimp (Crangon sp.) from Mike's Bait and the last of the live P. vulgaris from Sachs Aquaculture Systems. The frozen are much cheaper. For $5 I get about 10 days worth. I have not seen any aggressive behavior, but I did notice some mating behavior tonight. For now, there seems to be enough space that each cuttle get's their own rock/hiding space and they leave each other alone. I imagine this will change. During the day they rarely come out, but at lights out most of them swim around. It's hard to get a count of all eight and i need to count them as I feed shrimp with my feeding stick. Last night, however, was the first time in a while I could actually count all 8 because they were all out.