1. Home aquarists and
scientists agree- cephalopods can be really hard
to keep alive in a tank. They require a very clean,
stable seawater system, escape proof lids, and
they are picky eaters. Keeping one can be expensive,
and feeding one can be expensive.
2. While some countries have strict collecting laws, many tropical animals are collected from the wild using irresponsible and illegal methods such as poaching and/or “cyanide fishing”. Cyanide fishing involves squirting cyanide into the reef and breaking coral to dig out the poisoned, stunned animals. It kills coral, other invertebrates, and fish. Ask your aquarium shop for tank-raised animals.
3. It might be deadly. Blue-ringed octopuses are deadly. There is no anti-venom for their bite. Other octopuses are so poorly known that we don’t even know how dangerous they might be. Relatives of Abdopus aculeatus have a poison in their bodies that’s similar to TTX, the poison in blue-ring venom (Robertson et al. 2004 Toxicon 44: 765). Striking animals like “Wunderpus” and the “Mimic” might be highly venomous. It appears that the skin of the "Flamboyant" cuttlefish is toxic. You don’t want to be the one who finds out.
4. It might be rare, so taking a wild animal might put those cephalopod populations at risk.
5. It might try to crawl out. Octopuses are well-known for their abilities to escape aquaria. Intertidal species are notoriously hard to keep in a tank. If it goes walkabout when you’re not looking, then you will find a dead octopus on the floor the next morning, or behind the couch in two years.
6. It might eat your other pets. Crabs, clams and sometimes snails are not safe from the voracious appetite of a cephalopod. Often fish will either eat your cephalopod or be eaten by your cephalopods.
7. They don’t live very long, most species only about a year. By the time you get your tropical cephalopod, it is an adult near the end of its live span. You’ll be lucky to keep it alive for a few months.
With permission, this list is based heavily on
(in fact, some of it outright copied from) a similar
list by Christine L. Huffard, Ph.D. Thanks! Christine's
website can be found by clicking here.