August 1997

Q. I had a carpet anenome and a long tentacle anemone in a 55 gallon
tank with a protein skimmer, fluval 403 canister filter, heater, and
two powerheads connected to an undergravel filter for current. I kept
the light on for 14 hours per day using two 20 watt Coralife 50/50
bulbs. The gravel in my tank is crushed coral. I was wondering why my
anemones died? Are they suppose to be placed on large rocks that are
flat? If you could give me any further information on the care of
anenomes, I would greatly appreciate it. Thank you for your time and
thanks for answering my questions in the past. I think it is
wonderful that you actually write back to people who have different
questions.

Via the Internet

Unfortunately the above letter is typical of the problem that many
people have in keeping tropical sea anemones; they die more often
than not. This has prompted many to question keeping anemones in
captivity and to go so far as to suggest banning their import. This
is unfortunate because it is not impossible to keep anemones, its
just that the information required to do so has not been made readily
available. Having said this I must add that sea anemones are not for
the beginner. One should have a basic understanding of reef aquaria
and have success in keeping corals, zoanthids and corallimorpharians
before attempting to keep sea anemones. Familiarize yourself with the
species you wish to keep: where it is found in nature gives excellent
clues as to what kind of conditions it will require in an aquarium.
The Field Guide To Anemonefishes And Their Host Sea Anemones
by Daphne G. Fautin and Gerald R. Allen and published by Tetra Press,
is an invaluable guide to the clownfish host sea anemones commonly
available in the trade. It is excellent for properly identifying each
species as well as for providing natural history and habitat
information.

The above letter points some of the errors made when keeping anemones
in aquaria. The filtration, lighting and heating systems must be
designed with anemones in mind. Just about any filtration system can
be used to keep anemones but a number of factors must be addressed
such as keeping dissolved inorganic nitrogen compounds low (e.g.
ammonia, nitrite and nitrate), keeping organic levels low through the
use of activated carbon and/or adequate protein skimming, maintaining
adequate oxygen levels and providing good water movement. In general
the adage "the simpler the system the better" applies to keeping
anemones. The above filtration system should have been adequate but
there is no mention of the type or size of skimmer used. Also using
powerheads on the undergravel filter, depending on how they are
situated, do very little for the oxygen content of the water. They
should be positioned so that they cause a great deal of turbulence on
the surface of the water; this greatly improves gas exchange. Some
units have an optional airline that can be attached to create
thousands of air bubbles, but while these do boost oxygen levels they
tend to create a salty encrustation that can quickly corrode fixtures
in and around the aquarium. Also, if these encrustations fall and
settle on an anemone, they can cause serious harm to the animal! Water
movement is also critical for anemones as most come from areas with
good turbulence and flow, even if only during tidal changes. The
canister filter is probably of little use, other than to hold
activated carbon and provide additional flow, provided it is cleaned
on a regular basis (every week or two at the least).

Using a heater in an aquarium is fine, but in a tank with anemones it
can spell disaster! Since many species tend to wander, the chance that
they will settle onto a heater is great. When the heater turns on, the
anemone cannot move off quickly and its foot can be burned. This can
lead to tissue damage and often leads to infections. Either position
the heater in a separate sump or chamber, behind a partition in the
tank, or failing this provide a shield around the heater that allows
for good water flow but prevents anemones attaching to it e.g. a
perforated PVC pipe.

The biggest problem with the tank mentioned in this letter is the
lighting system. Like other reef inhabitants, many of the sea anemones
sold to hobbyists contain symbiotic algae called zooxanthellae. This
means these animals require light, and lots of it. The two twenty watt
fluorescent lamps on this tank were far, far from adequate and this
was most likely the reason for their death. Anemones require bright
light in order to survive. At least two VHO lamps should have been
used on this system, at the very least. Provided one can adequately
cool the aquarium, placing it close to a window where it can receive
several hours a day of sunlight is also very beneficial to sea
anemones.

In addition to the above there are a number of things that should also
be done in order to increase your success rate. Be sure to use screens
on all intakes of water pumps and/or powerheads. Anemones seem to be
attracted to areas of high water flow and often end up being attached
to powerhead intakes; a position that often results in sea anemone
puree! Although I mentioned that anemones have zooxanthellae they will
feed when offered food. Be careful not to overfeed; a small piece of
shrimp, scallop, squid or marine fish offered once a week or so is all
that is required. Sea anemones also seem to do best when trace element
solutions are added, especially those that contain iron and zinc.
There are a number of commercial supplements now available such as Two
Little Fishies' Combisan and Sera's MarinVit. Use these additions with
caution and never overdose!

Finally providing the correct substrate can be critical. For example
the Long Tentactled Anemone mentioned in this letter (most likley
Macrodactyla doreensis), lives in sandy areas and needs a sandy
or fine gravel bottom to do well. It will reach down below the
substrate and attach to the bottom of the tank. In contrast the
Bubble-tip anemone (Entacmaea quadricolor) lives in rocky areas
and will require rocks with crevices and large holes in which to wedge
itself. In the second volume of our book series The Reef
Aquarium due out this fall, Julian Sprung and I will provide more
specific details on anemone care and offer species by species
guidelines.

Anemones can be long lived in captivity provided the above criteria
are followed and a healthy specimen is obtained. At the Waikiki
Aquarium we have a carpet anemone (Stichodactyla mertensii) that
is over ten years old, and several colonies of Bubble-tip anemones
that are over seventeen years old and spawn each April! In fact as I
write this column (April 21st) I am expecting them to spawn sometime
next week!

In summary, please keep in mind the requirements of tropical sea
anemones BEFORE you purchase them, they are delicate animals and
require expertise and care to thrive in captivity. These are not
"disposable" animals, and if you do not have an adequate system to
maintain them, please do not order or purchase them!


Q. I am curious why most people still use a wet-dry system? In most of
the literature I am reading, this is still the most mentioned method.
I do not have any mechanical filter on my tank. The filter system I
am using consists of live sand, live rock, a protein skimmer and a
Rainbow Quiet One pump. I have no problems with ammonia or nitrate
build-up unlike all the problems I hear regarding the wet-dry system.

Jesse Williams
Grantsboro, NC

Well Jesse, that's what I've been wondering too!

Actually Jesse went on to mention he has trouble keeping fish due to
the predatory nature of his resident mantis shrimp. Although he has
tried trapping at several different times of the day, nothing seems to
happen. Mantis shrimp are very wary animals. If you are trying to trap
the shrimp you must allow it to get used to the presence of the trap
by placing it in the tank and leaving it there for several days, weeks
even, before baiting it. When baited the trap must be placed in the
tank and left overnight. Keep resetting the trap as often as required.
The trap should be a flow-through design so that the scent of the bait
(usually pieces of raw tiger shrimp) can easily spread through the
aquarium. Usually a piece of PVC pipe with mesh sealing off one end
and the other with a piece of mesh inserted in, in the shape of a cone
works well. The smaller opening of the mesh cone is inserted in the
PVC pipe and should be just large enough so the mantis shrimp can
barely squeeze through. This will make it harder to get out. Tip:
drill a small hole in one end of the pipe so that a piece of thread
can be attached; this will make it easier to pull out the trap.