
Jeremy
Squid are very difficult to keep. Much more than a similar sized octopus or cuttlefish!
1) you need a ginormous tank which must be cylindrical
2)they eat mega quantities of food, which must be live for most species
3)they get butt burn and infections very easily
4) they startle easily
However if you can afford a 2-5000L round tank, a fish market of live food every day and have a vet on standby you just might manage to keep 1 or 2
There are however sepiolids that you can keep more easily but they are fairly boring! They tend to be night active and bury in sand during the day, things like the bobtail and bottletail squid.
Most home ceph keepers give up on the idea of keeping squid and go for octopus or cuttlefish (see the ceph care articles for info!)
Cheers
Jean