The Pet Squid - Your Very Own Cephalopod
The truth is, having a pet squid will make as much sense for most people as having a pet rock. Unlike a pet rock, which is not all that entertaining after the first few seconds, a pet squid can be very entertaining, for a few minutes. Most cephalopods, which include the octopus and cuttlefish families, require intensive care and high maintenance to last very long, and many of the species have rather short life spans to begin with. On a scale of 1 to 10 for keeping a cephalopod as a pet, with 10 being easy, octopuses and cuttlefish rate around a 2 or 3, very difficult, the squid has a rating of 1, or slightly less.
The first thing you need for a pet squid is a large saltwater tank. If you place a squid in a freshwater aquarium, its life span will only be slightly longer than the life span of a lightning bolt. Even in salt water the pH has to be within quite narrow limits, the exact limits being dependent upon the species involved. The temperature must be kept within a tight range as well. A pet squid does not tolerate water that is a few degrees too warm or a few degrees too cold. In fact, a pet squid does not tolerate much of anything.
Move Slowly - If you do get a saltwater aquarium and manage to get the water at the right pH and the temperature exact, and keep the water carefully filtered, the other thing besides food you need for your pet squid is a semi dark room. Squid do not like bright lights, not do they care much for any movement they don't understand. When you enter the room you need to enter slowly and make no quick movements. The squid is highly unlikely to get used to you or recognize you in the course of its lifetime. Unlike many pets, including many fish, your squid isn't going to greet you at the side of the tank when it sees you bringing dinner. It's much more apt to head for the opposite side of the tank at warp speed, spewing ink, and running into the glass wall with a tremendous force. The end result will most often be a slightly battered squid located somewhere in the inky blackness of the tank. The average pet squid can't take that type of stress and battering day in and day out for very long
Travel Is Stressful - Unless your local saltwater pet shop has squid in stock (they’re more likely to have an octopus or two if anything in the cephalopod line), you'll have to mail order one. Even for a small squid shipping can be expensive, as you'll be paying to ship a couple of gallons of water as well, and usually paying for overnight or next day shipping. Since, like most everything else, shipping is very stressful for the squid, you might want to order 20 or 30 of them in the hopes that at least one will arrive alive. Assuming it does arrive in fine shape, when you introduce it to its new aquarium home, the first thing it's apt to do is travel at warp speed to the far side of the aquarium, and bash its head against the glass wall.
The Bottom Line - While all of this might seem designed to discourage you from trying keep a squid as a pet, it's really designed to help you avoid a whole lot of trouble. Serious saltwater aquarium hobbyists will from time to time invest in an octopus or cuttlefish, and with proper care can enjoy their acquisition, unless or until it outgrows its living quarters. There aren't all that many documented cases of anyone successfully keeping a pet squid however. Chances are the only places you'll see a squid in captivity are in large commercial aquariums or in tanks where they're being studied. Even in those environments, they are generally considered to be high maintenance items. But, if it's a real challenge you're looking for...