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Cuttlefish in the Home Aquarium Part 1

In August, I began a project that I’d wanted to do for a very long time: keeping dwarf cuttlefish in a home aquarium. I’ve been a long-time aquarist, and have even kept octopuses on a few occasions, but cuttlefish had always been hard to come by. In August I received a shipment of 5 eggs. This series is going to be an overview of my cuttle-keeping adventures.

What Are Cuttlefish?

Cuttlefish are cephalopods, which is a group of marine mollusks that also include octopuses, squid and nautiluses. Cuttlefish have almond shaped bodies, with a fin skirting the outside edge all the way around. They have large eyes, with “W” shaped pupils. Like octopuses, they have eight arms lined with suckers, and a sharp, parrot-like beak at the center of those arms. Unlike octopuses, they also possess two feeding tentacles with club-like ends that they use to catch their diet of mostly shrimp and crabs. Cuttlefish are also masterful camouflage artists, able to change color and texture almost instantly and frequently use their color-changing abilities to communicate with and intimidate other cuttlefish.

Keeping Cuttles:

The species most accessible to hobbyists in the USA are a dwarf cuttlefish called Sepia bandensis. Fun fact: the word “sepia,” often used in modern digital photography to denote a brownish filtering, originates from cuttlefish, as that brownish coloring was once derived from the ink of these animals. Bandensis cuttles are about 4.5 to 5″ long as adults, and often display brownish stripes or bands on their bodies.

Tank, sump, skimmer.
Tank, sump, skimmer.

Before acquiring my cuttlefish, I spent close to a year preparing and researching and building my tank. I used a 40 gallon “breeder” tank (a low, wide aquarium), had a hole drilled out of the back of it, and plumbed a 20 gallon sump below it. Cuttlefish and other cephalopods produce a lot of waste, so a tank with a lot of flow is necessary.  I used a 500 gallon per hour pump to get water from the sump back up to the display tank. For filtration, I used a CPR Bak-Pak protein skimmer and about 100 pounds of live rock. (That’s porous, bioactive rock from the ocean that seeds the tank with bacteria that eat ammonia, i.e. waste). In order for those bacteria to take hold and be at high enough concentrations to effectively handle the massive amounts of waste from the cuttles, I allowed the aquarium to cycle for 4 months. During that time, ammonia, nitrite and nitrate had spikes and came back down to acceptable levels, and a good number of organisms that hitchhiked in on the rock took hold and started to grow. Featherduster worms, snails, a few hermit crabs, tiny starfish, etc.

Once I was certain I had a tank that was ready, I ordered my eggs in late August. (Actually it was on H.P. Lovecraft’s birthday, August 20th!) and 5 little eggs about the size of small grapes and coated with ink arrived. Cuttlefish EggsWell, actually, 3 eggs arrived in pretty good shape. Two of the eggs were deflated, and unfortunately had hatched in the bag during shipping. I had what looked like 2 DOA cuttles. Well, one of them was. Turned out, the other one was still alive and started moving about 6 hours later (lucky I didn’t remove him right away), and I’m happy to say “Lazarus” is now one of the biggest individuals in the tank. So I ended up with 4, tiny, hungry little krakens that I needed to start finding food for.


To be continued!


Ethan Kocak writes, draws and otherwise cobbles together comics on the internet.

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