Octopuses are interactive, intelligent and appealing. Jason Scott of The Water Zoo explains the difficulties inherent in keeping these specialised cephalopods.
Over the past twenty-five years or so I have kept a wide range of strange and unusual marine species; everything from sharks and rays to Frogfish and Flying gurnards. In this time I have accumulated a good deal of knowledge about how to care for the weirder aquarium inhabitants.
For many years, keeping an octopus had been a really appealing idea - I was fascinated to learn for myself whether the stories regarding their intelligence and camouflage were true. I had heard rumours that they were extremely difficult to keep but, always ready for a challenge, I decided to take the plunge.
The first problem I came across was a complete lack of information on keeping an octopus in a home aquarium. I found lots of information about various species, but absolutely nothing about water conditions, filtration, aquarium size, behaviour and other crucial factors.
The first aquarium was 68 l./15 gal. and equipped with a Bak-Pak skimmer with built-in biological filter. An eight-watt fluorescent tube provided lighting - this was the smallest available, but still a little too bright. For decoration I used 10 Kg/22 lbs of live rock.
After the aquarium was matured I obtained a small Red octopus, I later found out this was an extremely nocturnal species, Octopus bocki. Identifying any octopus correctly is difficult, even for experts. This species only comes out in complete darkness and does not exhibit many of the character traits associated with other more diurnal octopuses, for example, colour changes.
It fed well on cockles still in their shell and it used the empty shells to form a barricade to its hole in the live rock where it lived. This did well for two months, before it got stuck behind its own barricade. It was trapped for several days before I realised and when it was released it was very distressed and died the next day.
Over the next few months I tried to keep octopuses in this aquarium on several occasions without success. They did well initially, but then stopped feeding and then deteriorated very quickly. I tested the water frequently and never found anything to be concerned about.
Unfortunately I was not sure what the parameters for octopuses should be. In hindsight there may have been inadequate oxygenation and circulation or a low s.g. I had never been so unsuccessful in keeping any species before and octopuses were rapidly loosing their appeal due to my failures. I decided to throw everything I had (including over two and a half thousand pounds) at one last attempt...
Resources at the ready
I purchased a 91 x 66 x 51cm/36" x 26" x 20" custom-built aquarium designed to house an ab Aqua Medic Marin 500 internal filter, this includes a large air-driven protein skimmer, trickle filter and a D and D Sulphur Denitrator. The Marin 500 is rated for tanks up to 590 l./130 gal., I installed it on my 181 l./40 gal. tank to ensure that inadequate filtration was not going to be an issue. (...)
Jason Scott is Practical Fishkeeping's Equipment Answers expert. He owns and manages The Waterzoo in Peterborough, which was voted one of the UK's Top 40 Shops by readers of this magazine. Jason has kept and bred fish for over 25 years and is particularly experienced with unusual marine and freshwater fishes, as well as inverts and aquarium technology.