Tropical Fish Hobbyist

The dwarf cuttlefish Sepia bandensis is one of the coolest animals on the planet. It zips through the water like a little UFO, able to instantly change direction and speed. As it darts around the tank, it can change the color and texture of its skin— going from static rock-like camouflage to patterns flowing across the canvas of its skin in an instant. Sepia bandensis is a phenomenal predator, patiently stalking a potential meal before shooting its two feeding tentacles forward, like a lizard’s tongue, to snatch its prey. It will even come to the front of the tank to greet you when you walk into the room (although it may just recognize that you are the source of food). Best of all, it won’t try to climb out of the tank like its eight-armed octopus cousins. All in all, it is one of the most fascinating animals I have ever had the opportunity to keep in aquaria.

Wild-collected adult Sepia bandensis ship poorly, with high mortality rates, and because they are adults, they may only have months or weeks left to live when they finally arrive at your home. However, in the last few years, alternatives to wild-caught adults have presented themselves.

Daniel Pon

Cuttlefish, like many cephalopods, are able to change the color and texture of their skin depending on their mood and environment.

Wild-caught eggs appear on the market with regularity, and our understanding of how to raise the eggs and hatchlings has advanced greatly. Even more exciting is the success people have had captive-breeding Sepia bandensis, and captive-bred eggs and hatchling cuttles are offered for sale by breeders with increasing regularity. This means that not only is nothing taken from the wild, but the availability of Sepia bandensis is no longer dependant on the seasonal availability of wild animals.

Cuttlefish Basics

Sepia bandensis is a cephalopod, related to the octopus, squid, and nautilus. S. bandensis have eight arms, two feeding tentacles, three hearts, a ring-shaped brain, a cuttle bone that helps control buoyancy, a fin that girds their mantle for fine maneuvering, a funnel that gives them jet-like propulsion, superb 360-degree vision (though it appears they are color blind), copper-based blood, and the ability to squirt ink. They mate readily at around five months old and lay clusters of ink-covered eggs that resemble bunches of grapes. When the hatchlings are born they are tiny and measure less than ¼ inch long, but they can grow to an inch long within two months and to about 4 inches within six months.

Three- or four-month old cuttlefish simultaneously striking at prey with their feeding tentacles. The tentacular club at the end of the feeding tentacles of the animal on the right is clearly visible.

An Awful Truth

Dwarf cuttlefish only live about a year. What makes this short lifespan even worse is how many cephalopods die: They go into what is called senescence. During senescence, the cephalopod essentially wastes away. They become listless and their eyesight and coordination start to fail, causing them to have difficulty hunting or even accepting food placed directly into their arms. Sometimes their arms and body will begin to rot in place. I have seen hermit crabs feeding off still-living Sepia bandensis while the cuttlefish does nothing, showing no signs that it is

even aware of what is happening.

In the wild, a cuttlefish going through senescence doesn’t last long, as it is quickly eaten by other animals. In captivity, however, with careful feeding by the aquarist, it is possible for such a cuttlefish to linger for months while slowly declining. I bring this up because it is important to be ready for this aspect of keeping a cuttlefish, and to drive home the point that captive breeding of these animals is important. If you captive breed them, it seems to somehow make the short life of the animal feel less tragic and more meaningful.