In this issue
we offer several especially valuable articles. Firstly, this
month's short take is especially valuable because it illustrates
with clear graphs why small water changes are, if not useless,
not especially useful. For many, the question of whether to
periodically change some water is in itself questionable.
Often we hear from experienced aquarists statements like,
"I haven't changed water in X months and everything is
still fine." To my knowledge there isn't enough scientific
study to definitely clarify this question, but mine and other's
anecdotal experience clearly indicates that regular, substantial
water changes are an important way to keep a closed system
reef tank healthy. In short, change water periodically, and
change enough water to make it worth the effort. But, be sure
that the make-up water is of higher quality than the water
to be replaced, prepare the new water from RO/DI freshwater
or the equivalent with a quality artificial salt, and be sure
that the make-up water is of the same temperature, pH, and
salinity as the water to be replaced. Not following these
details may unnecessarily stress the established animals,
and as many of our authors have pointed out, stress weakens
our captive animal's immune systems.
Charles Delbeek,
one of our media columnists, reports in detail one scientific
study which makes it clear that when the scleractinian coral
Stylophora pistillata is fed, apart from what they
it gets from its symbiotic algae (zooxanthellae) it grew faster
with a denser skeleton.
We have reached
a place in our hobby where many of the challenges of the past
have been solved, but for those of us who like challenges,
there are still plenty. Keeping in captivity invertebrates
that are not partially fed by their symbiotic algae and must
get all of their nutrition by capture and filter-feeding we
are beginning to have success in feeding some of these. Sponges
are beautiful and fascinating, but few if any of us have had
long term success in keeping some of the most beautiful sponges.
Who wouldn't want to have one of the barrel sponges photographed
by Greg Schiemer, pictures of which are in Rob Toonen's column?
In his first paragraph Rob says, I think that there
are really two primary reasons for the unfortunate failure
of most hobbyists with sponges in their aquaria. The
first reason is that most collectors and hobbyists are ignorant
of sponge biology, and do not realize that removing most reef
sponges from the water, even for several seconds, will kill
them (I will explain this in more detail below). Second,
very little is known about sponges even within the scientific
community, and their physical tolerances and husbandry requirements
remain as much a mystery to marine biologists as they are
to reefkeepers. Sponges are quite a challenge. The
photo with this editorial was taken by me 15 years ago - it
shows its age - and shows a lavender sponge attached to the
side of a Tridacna gigas. The sponge came from somewhere
and after growing rapidly for several weeks disappeared. The
sea world still withholds many of its secrets.
