Author: Colin Dunlop
Considered the ultimate invertebrates by their fans, the otherworldly cuttlefish make great pets for those willing to meet their very specific needs.
It is an amazing time to be involved in the marine aquarium hobby. If you do the necessary work you can even keep a cephalopod at home. Knowing it’s possible, why not consider the possibility of keeping cuttlefish?
Seven years ago I could never have guessed just how large the interest in cephalopods would get. Sure, it takes a certain kind of person to keep one, but their popularity has truly blossomed; what once was a handful of interested people swapping scant information in online forums has grown to thousands of hobbyists sharing their exciting progress in countries all over the world. All the information you need is online and available to anyone (there are no books about keeping cephalopods). This line of invertebrate-keeping is still so new that it doesn’t take long to come up with a brand-new discovery regarding their husbandry and life cycles.
Most budding “cephaloholics” get drawn into the idea of keeping cephalopods in home aquaria by the enchantment and wonder of an octopus. Lots of people have heard about them opening jars, shaking hands, and having an uncanny alien intelligence. There is, however, another breed of keeper out there who finds that the cuttlefish is the ultimate invertebrate for their attention.
My Cephalopod History
My cephalopod husbandry began after I had the idea that it would be interesting to have a pet cuttlefish. I hadn’t had access to the Internet for very long, and it had opened up a whole new world for me as far as researching future aquatic projects were concerned. Actually, I remember that within a few hours I had managed to track down a supplier of common European cuttlefish Sepia officinalis with newly hatched babies for sale.
I had an initial advantage because I live in Scotland, and Sepia are commonly found around the coasts of the southern United Kingdom. Much to the frustration of North Americans there are no Sepia species naturally occurring in the waters around the United States. What’s worse is that cuttlefish seem to handle shipping very poorly, especially if it lasts more than a day or so. Unfortunately for North Americans, trying to obtain imported species through normal fish importers is very tricky.
After sorting out the logistics of converting a 200-gallon tank, I initially ordered five baby Sepia officinalis that were just two weeks old. Best described as captive farmed, the eggs are collected from lobsterpots in the English Channel and hatched out in large vats by a cuttlefish aficionado. (He actually supplies cuttlefish and their eggs all over the world for universities and public aquariums.)
They were sent by overnight courier and were lightly sedated to help them with the transportation. Later the next day they turned up at my door in very good condition, especially considering that they had traveled the length of the United Kingdom in just one night. On opening the box I discovered that I had been sent seven instead of just the five I had ordered; that’s two for good luck!
Thankfully I had also been supplied with a lot of good practical information, and most of it still holds true today. One helpful fact I had learned was that the acclimation of cephalopods is of paramount importance. It has to be done slowly and with water that has parameters as close to true sea water as possible. For example, many hobbyists who keep “fish only” systems may have greatly reduced salinity levels to try and prevent parasites in the aquarium. Salinity levels more than a few parts per thousand from 32 will result in a cuttlefish’s death. Likewise the pH must always be above 8. If you set up a cuttlefish tank the same way you would go about setting up a reef tank, then you won’t go too wrong.
The young cuttlefish were about 12 mm long and were put into a mature aquarium measuring 36 x 15 x 15 inches with water parameters of pH 8.2, ammonia and nitrite 0, and nitrate of 10 ppm. I took more than an hour using a dripping airline to gradually add the new aquarium water. Most importantly, Sepia officinalis is not a tropical species, so the tank was unheated and temperature sat in the mid 60s.
The aquascaping was kept very basic and consisted of a one-inch-deep layer of fine, well-washed sand. An internal filter was used for filtration, there were no lights above the tank at this stage, and hiding places consisted of a few halved clay plant pots. The cuttlefish were gently scooped out of their bag with a whisky glass and carefully poured into the tank.
One of the babies decided to demonstrate its ability to squirt ink while being moved, and it was amazing to see. At this age the young cuttlefish eject a blob of ink that holds its shape for a few moments, while at the same instant they make a sudden dive for the substrate and bury into the sand. The theory is that the assumed predator gets momentarily confused by the blob and bites it while the young cuttle escapes. Although non-toxic, the ink produced by Sepia species certainly doesn’t seem to taste very good and is thought to cover taste buds and cause confusion. These small pseudomorphs can be netted out with a fine net.
Feeding cuttlefish is anything but easy. It’s not that they are particularly tricky to feed, just that they eat lots of food, and newly hatched cuttlefish and juveniles of up to about 2 to 3 inches in total length require live food and will not accept non-moving items at all.
The right kind of food has to be offered, and in this case live brine shrimp just doesn’t seem to cut it; many people have failed at rearing cuttlefish with Artemia. The main diet of cuttlefish in the wild is crustaceans, and to a lesser extent fish. I decided that Crangon crangon, a locally caught shrimp found on sandy beaches near my home, would be perfect. I just didn’t realize that the cuttlefish would eat so much! A 15 mm cuttlefish will easily go through three or four 15- to 20-mm shrimps per day.
Don’t Use Feeder Fish
Let me also steer you away from using live feeder fish. It seems a much more common practice in the United States as opposed to the United Kingdom, but it’s really not recommended. It is mostly freshwater fish like goldfish that are used as feeders, and apart from the fact that they don’t offer the correct nutritional value, they also might have been treated for disease with copper-based medications. As is the case with a lot of other invertebrates, copper is deadly to cephalopods.
Watching them hunt their food is truly amazing. A cuttlefish can change color in the blink of an eye and even extend flaps of skin to change its overall texture, too. They will sneak up on a shrimp from behind, and once it is in striking distance the cuttlefish shoots out a pair of long feeding tentacles and pulls in the meal. There is no escape.
Bigger and Badder
In time the cuttlefish grew, and within a couple of months I moved them into their larger quarters. The filtration was a large homemade trickle tower and an equally large protein skimmer. The tank was actually set up as a reef tank with hardy corals and no other non-sessile species, which would be seen as a snack. The only other inhabitants were the cleanup crew, which consisted of a few brittle stars, turbo snails, and some red leg hermits—all of which were largely ignored. Amphipods and bristleworms appeared from the live rock, and although the amphipods were eaten at first, once the cuttlefish grew they were ignored and their population exploded.
Luckily by this stage I had managed to wean the cuttlefish onto non-living foods, and getting suitably sized raw frozen shrimps from the local seafood shop was a lot easier than catching shrimp every couple of weeks and keeping them alive. As far as crabs are concerned, I would go to the rock pools and collect enough shore crabs for a month or so. Then I would take them home and freeze them myself.
Sexing and Feeding
Sepia officinalis can get to a size in the wild approaching 18 inches in total length. After about six months my seven were ranging from 3 to 6 inches, and I started to make out some possible differences between the sexes, namely the males being larger and more territorial.
It was around this time that I had a casualty. Fighting during feeding times was fairly frequent and normally happened when two cuttlefish would fight over the same item of food. However, apart from a few sucker marks the fights looked worse than they were. There was one exception. One day when I tried to feed them squid from the local seafood shop they loved it, but I think this may have given them the taste for cephalopods. The next day one of the larger cuttlefish decided that cuttlefish and squid tasted similar and ate one of his smaller tankmates. I never fed them squid again, and they never cannibalized each other again.
“Live Fast, Die Fast”
My cuttlefish were getting big, so some were sent to a public aquarium in Ireland. Catching them resulted in my tank turning jet black with ink. It was the only time that they ejected a lot of ink, and I was glad that I had such a large skimmer to cope with it all. It took the best part of two days to be removed, and the collection cup was a black inky mess.
I kept two of the cuttlefish and they grew to about 12 inches long within the tank. I was pretty sure I had a pair, and this was confirmed when I caught them spawning. The male was inserting his specially modified arm, called a hectocotylus, into the female’s body cavity to transfer sperm. However, she died the next day from wounds from the male. I can only assume as to what went wrong, and in retrospect I think that perhaps she wasn’t ready to spawn and got bullied.
My one remaining male lived in the tank until he was just about a year old and then died of old age. That’s another cuttlefish drawback: they are naturally very short-lived. Their motto could be “live fast, die fast.”
A cuttlefish in an aquarium at the local fish shop is more than likely to be a Sepia bandensis. Other species do surface from time to time, but S. bandensis is the most commonly seen. This little cuttlefish, originally from Indonesia, is fully grown at about 5 cm (2 inches) mantle length. If the cuttlefish is close to that size then assume it is wild caught, unless the shop staff can tell you otherwise.
The chances are that it will just be labeled as “cuttlefish” and there will be no scientific name accompanying it. This is very frustrating and can lead to problems associated with husbandry. Is it a 2-inch cuttlefish fully grown, or is it a baby of a species that will be fully grown at 36 inches? There are several species it could potentially be, but S. bandensis seems to be the most common.
Problems with Wild Catches
There are two main problems associated with wild-caught cuttlefish that also apply to S. bandensis. As you now know, our cephalopod pals are not all that long-lived, with less than 12 months being about the norm for longevity. Lots of pictures have been posted in online forums displaying newly purchased cuttlefish that unfortunately showed the purchased species to be sexually mature adults. This means that they have very little of their natural lifespan left to live. Apart from anything else, this purchase is not exactly good business sense, as they have been seen for sale at up to $100 each. It can be an expensive way to keep a cuttlefish for a couple of weeks before they die of old age.
In more recent times there have been importations of egg clusters of S. bandensis into the shops, both in the United Kingdom and United States. Even more exciting is that some hobbyists are now on their second generation of captive-bred bandensis, which they originally bought as eggs. Captive-bred specimens are becoming far more common, and I wholeheartedly suggest that you track these down if you want to give cuttlefish a try. Shipping eggs is very easy and they have a high success rate of hatching, but just remember how much feeding they need.
S. officinalis was becoming easier to get in the United States for a while after harvested eggs were shipped across from the United Kingdom, but this source has literally dried up, and only universities and research institutes are able to easily get them again. It’s maybe not such a bad thing, as they grow so big and are not a tropical species.
On occasion, the flamboyant cuttlefish Metasepia pfefferi has been imported into the United States. The highest price I have seen them going for was over $200. Just like some of the original S. bandensis, these cuttlefish were fully grown adults likely to die of old age in a short amount of time.
Avoid buying these, and that will hopefully discourage exporters and catchers from pursuing them. There is not enough information about their status in the wild, a similar situation that faces octopuses like “wunderpus” and “mimic.” A couple of M. pfefferi have lived longer than a couple of months in captivity, but not many. I personally don’t see the point in buying a single specimen with not much time to live and no chance of breeding.
Sepia bandensis is an ideal species of cuttlefish for captive husbandry. They don’t grow as large as the other species, obtaining a total length of about 10 cm (4 inches). They also seem quite willing participants for a breeding project, even for beginners. I thoroughly enjoyed keeping Sepia bandensis a year or so after the officinalis, and the fact they can be kept in much smaller aquariums that are set up like a modified reef tank is a huge bonus.
Sepia officinalis is a much larger beast that’s expensive to cater for, but it’s worth it if cash isn’t an issue. Make sure to really consider your decision before purchasing a cuttlefish, especially regarding their diet; it can get expensive feeding them, and if you can’t supply the correct food in the right volume then they might not be for you. Their short life expectancy might put off a lot of people, as well. It’s a shame that such an intelligent and interesting group of animals has such a short lifespan.
For Further Information
Boyle, P. R. 1991. The Care and Management of Cephalopods in the Laboratory. Universities Federation for Animal Welfare. Hertfordshire, United Kingdom.
Dunlop, C. 2003. “Cuttlefish Basics.” Available at: http://www.tonmo.com/articles/basiccuttlefish.php.
Norman, M. 2000. Cephalopods A World Guide. ConchBooks. Hackenheim, Germany.
Norman, M., and A. Reid. 2000. A Guide to Squid, Cuttlefish and Octopuses of Australasia. CSIRO Publishing. Victoria, Australia.
Moynihan, M. 1985. Communication and Noncommunication by Cephalopods. Indiana University Press. Bloomington, Indiana.
The Octopus News Magazine Online: www.tonmo.com.
The Cephalopod Page: http://is.dal.ca/~ceph/TCP/index.html.