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.
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.
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
Tropical Fish Hobbyist www.tfhmagazine.com