hm... I'm thinking probably not. You could get away with it for a little while before they grow too much.
They will very often turn on eachother! The NRCC feeds them three times a day to prevent it. Because of the sheer volume of food consumed, they switch them from live grass shrimp to large thawed shrimp. Many times, some cuttles refuse this at first and just grab onto his neighbor and start gnawing.
flambouyant cuttles are metasepia pfefferi... i have looked into them and decided they might be too hard to obtain even though they are found in my area of Australia - though they arent as common as others.
The reason is that because they stay so small, most that are caught are adults ready to die - bummer
If the NRCC had no luck breeding then i probably won't either...
I have decided on sepia mestus (reaper cuttle) which are also in my area and grow to 15cm ML (mantle length) They are also much easier to identify so as not to confuse them with latimanus (which grow to 50cm ML)
Im not sure if they have been kept in an aquarium but stay in lifelong pairs in the wild withough fighting so they are worth a try!!!
Chances of seeing a metasepia for sale is pretty slim and they would cost a bomb. I saw a flamboyant once at a LFS aand it was going at only $15. He probably got it by chance and didn't realise its value. Someone got to it before me though :(
for pharaohs i have heard anything from 30cm (NRCC) to 45 (record from cephbase or somewhere for a wild caught adult) I think this is due to the range of temperatures they live in. eg Thailand, Australia, Aquariums... even just along the Aussie coast the temps have a range of several degrees.
Sorry i didnt make it clear... i have only ever seen one ceph in a pet shop in Aus, though octos are more common,this was an unidentified squid
For this reason i am looking into trawlers, i have a few trawlers who are willing to help me so far though i need to look into species more thoughroughly. I am planning a visit before pickup to suss out the species.