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Cuttlefish Husbandry: Part III - How do I keep a cuttlefish?<< Cephalopod Articles | Photographs and text by Dr. James B. Wood
Parts one and two of this article on keeping cuttlefish described what cuttlefish are and how to purchase one. Our intrepid readers (that is you) were left hanging with this question in their minds: How do I keep one? This section will bring our intrepid readers up to speed on the filtration, foods, tank sizes, tank mates and lighting needed to successfully keep one of the most interesting creatures on the planet, the common cuttlefish.
There is a plethora of books on the market that cover the science and art of setting up a marine aquarium. As this information is already readily available I will concentrate on specifics that apply to cephalopods. Hobbyists that are interested in keeping a cuttlefish and aren't yet familiar with the nitrogen cycle, the use of protein skimmers, pH, salinity, and the importance of regularly testing water quality are strongly encouraged to read several books on the subject first. Cephalopods aren't as hard to keep as many think; however, I'd advise against keeping them in your first marine aquarium.
Cuttlefish should be provided with well oxygenated, clean water. They are very sensitive to heavy metals, especially copper. Copper probes or chiller coils can not be used and metals should be kept out of the aquarium. 'Aquarium safe metals like stainless steel and titanium may be OK but should be kept to a minimum.
Since cuttlefish grow fast, eat a lot, and are active, it would be a good idea to slightly over-filter the tank. Canister filters, turf scrubbers, hang on the backs, wet/drys, fluidized bed filters or whatever the latest flavor of filter is, can all be used on a cuttlefish tank. Undergravel filters are not advised as cuttlefish often dig in gravel which could create dead spots. Also, the cuttlefish may get stressed when the gravel is cleaned. If you have small cuttlefish, place a sponge over the filter intake so that the cuttlefish does not get pinned to it.
No matter what you use as a filter, I would advise adding a protein skimmer, even if it is just a small one. Protein skimmers remove some waste products even before they decay into ammonia, and they also create a lot of water/air surface area which keeps the water well oxygenated. Carbon and/or resins like polyfilter can also be added in the filter. They remove unwanted organics as well as ink and heavy metals. Water changes of about 20% should be done monthly, and pH, salinity, ammonia, and nitrite should be monitored. Cuttlefish will ink if stressed. The ink should be siphoned out of the aquarium, and the cause of the stress should be located and removed if possible.
Cuttlefish should be housed in well established tanks—preferably ones that have been up and running successfully, with a biological load in them, for at least 3-4 months.
Cuttlefish don't need any special kind of lighting. Keeping the lights to a minimum also reduces the growth of algae and one or two standard flourescent bulbs will suffice. Those keeping reef tanks and using much brighter lighting need not worry as the intense lighting will not bother cuttlefish; rapid increases in light level will though. New cuttlefish are especially prone to inking if their environment rapidly changes. For example, if someone bumps the tank or the lights come on suddenly they may ink. In addition to inking, nervous cuttlefish may react by jetting and hitting the side of the aquarium. This can cause the delicate skin to rip, exposing the muscle below, and is termed 'butt burn' by Dr. Jean Boul. This lesion can get worse if the animal continues to jet into the side of the tank and it can become infected. If you see this happening turn on the lights slowly and try not to startle your cuttlefish.
Cephalopods live from the poles to the tropics and from the intertidal to the abyss. Sepia officinalis isn't a tropical species and it should be kept between 15-25°C (59-77°F). If your live in a warm climate, a fan blowing over the top of the water and moderate lighting is often all that is needed to cool a tank down enough for Sepia officinalis. If you buy a cuttlefish from a pet store try to find out where it was collected so you can make an educated guess regarding the temperature at which to keep it.
Cuttlefish such as Sepia officinals, are more social than octopuses and are generally found in loose groups in nature. A group of cuttlefish can be raised together in a large aquarium. However, if an adult male that has been raised by himself is introduced to another adult male they are likely to fight and may damage each other. Keep in mind that if food is limited, cephalopods can be cannibalistic.
Fish one intends to keep should not be kept with cuttlefish, they will either become dinner for them or vice versa. Like myself, cuttlefish will devour any crustacean in sight, so please keep them out of their tank unless they are intended as food. Cuttlefish might not be able to get hermit crabs out of their shells but they will certainly try. They generally leave echinoderms alone (sea stars, brittle stars, sea cucumbers) though there are a few exceptions. Some cephalopods will eat bivalves, snails and worms while others do not. They won't try to eat the anthazoans (coral, sea anemones, zooanthids, etc), sponges and tunicates (sea squirts) found in reef tanks. However, some of the more aggressive hard corals can sting them. This is more likely to occur to octopuses as they usually are in contact with the bottom. Both cuttlefish and octopuses may move things like gravel and small rocks around.
Tank size, of course, depends on the size, and the potential size of the animals that you are planning to keep. Some species like Euprymna scolopes, are small and can easily be kept in a ten gallon aquarium. Other species like Sepia officinalis get much larger - one of ours is approximately 15 inches long. I'd recommend at least a 40 gallon aquarium for a single Sepia officinalis. A larger tank certainly wouldn't hurt. (UPDATE/CORECTION: ACTUALLY I WOULD RECOMMEND 100 GALLONS PER ADULT CUTTELFISH. GROUPS OF SMALLER CUTTLEFISH CAN EASILY BE HELD IN MUCH SMALLER TANKS BUT AN ADULT COMMON CUTTLEFISH NEEDS MORE ROOM THAN I PREVIOUSLY INDICATED. ADULT MALES MAY NEED TO BE SEPERATED EVEN IN SYSTEM THAT IS 15 M DIAMETER.)
Cuttlefish primarily eat live marine fish and crustaceans in nature and these are ideal foods for them in captivity as well. If you are lucky enough to live near a beach, estuary, or marine bait shop and can give your cephalopod live food it will love you forever. Healthy cephalopods eagerly go after live food and seem to be always hungry. A cuttlefish that hasn't eaten in a few days and does not go after live food is very ill. Unlike most octopuses, cuttlefish will still eagerly take food after they start laying eggs.
Luckily for inland aquarists, adult cuttlefish will often take frozen food such as frozen shrimp and fish and such foods can make up their staple diet. Variety is the spice of life for cephalopods as well as humans. Most large grocery stores have a good selection of frozen marine shrimp, crab, lobster, mussels, squid, and fish to chose from. It may be necessary, especially at first, to skewer frozen food and swim it around the tank to get a feeding reaction. If you have been feeding frozen food for a while and are having problems feeding try temporarily switching to live food. Live freshwater crustaceans such as freshwater shrimp, crayfish and fish can also be used. Although live freshwater foods are not quite as nutritious as their marine cousins, cephalopods will grow and thrive on them, and they do elicit a healthy feeding response.
Cuttlefish do eat a lot, but like most marine creatures they can be overfed. A healthy cuttlefish that feels secure in its surroundings is very likely to 'beg' for food and train its owner to give it more than it needs - especially if it is being fed live food. Excess, uneaten food should be removed, as it will rot and may cause an ammonia spike. Proportions should also be reduced past the point where the little beast is able to eat everything. If your cuttlefish isn't eating very much of the frozen food that you are offering, switch back to live food for a while.
Underfeeding can also be a problem. Cephalopods can be cannibalistic especially when they are underfed. Boletzky and Hanlon (1983) report that one of the first signs of under feeding is the appearance of a dark longitudinal stripe on the dorsal (top or upper) side of the mantle.
Cuttlefish generally eat the meat out from crustaceans and discard the shells, but they ingest entire fish. Cuttlefish have a large cuttlebone, and they may get some of the calcium for it from their diet. It might be a good idea to occasionally fed them whole fish, either live or frozen.
Now you not only know where to purchase a cuttlefish, but what to feed one, how to filter the tank and what tank mates are likely to remain alive. There is only one question left. The question that all serious marine aquarists in this modern age want to know. The question that proves beyond a doubt to our spouses that our 'curiosity' with marine life goes well into the realm of obsession. The question that separates the amateurs from the truly addicted aquarists. The question: Can I breed them? See ya next month for the final section of this article and the answer to that question.
ReferencesBoletzky S.v. 1983 Sepia officinalis. In: Boyle, P.R. (ed) Cephalopod life Cycles, vol 1. Academic Press, London. 31-52.
Boletzky S.v. and Hanlon R.T. 1983. A review of the laboratory maintenance, rearing and culture of cephalopod molluscs. Memoirs of the National Museum Victoria, 44: 147-187.
Boyle P.R. 1991 The UFAW handbook on the care and management of cephalopods in the laboratory. Universities Federation for Animal Welfare.
Articles ReferenceWood, J. B. 1998 Cuttlefish Husbandry. Part III; How do I keep a cuttlefish? Freshwater and Marine Aquarium Magazine. vol 21, no 9. Reprinted in: The Cephalopod Page. Wood, J. B. Ed.
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The Cephalopod Page (TCP), © Copyright 1995-2014, was created and is maintained by Dr. James B. Wood, Associate Director of the Waikiki Aquarium which is part of the University of Hawaii. Please see the FAQs page for cephalopod questions, Marine Invertebrates of Bermuda for information on other invertebrates, and MarineBio.org and the Census of Marine Life for general information on marine biology.