This article represents the last part of
a three part series covering the many and widely variant sources
of reef fallacies and suppositions. As I mentioned at the
end of the last part in the series, the list I have made here
is by no means exhaustive, and one could practically continue
with such a listing for a very long time, and for a great
many words. I fully envision a whole new series of articles
as being possible within a relatively short period of time.
This is unfortunate, but stems largely from the fact that
reef keeping is still a relatively new practice, and there
are vast areas yet to be understood more completely.
It is fortunate that as the numbers of
aquarists increase, so do the number of significant findings
associated expressly with aquariums. Using information based
on the biology and ecology of natural communities, physical
and chemical canons, and general scientific bases is a strong
start. Yet, there are idiosyncrasies and specificities that
occur in aquariums that are unlike anything found in nature.
As such, more direct, careful, and judicious experimentation
will quickly lead to the elucidation of many of the artifacts
of closed system aquaria.
Myth 14: Microbubbles are to be avoided.
Many aquarists go to some considerable
lengths to baffle sumps and pump flows to prevent small bubbles
from being returned into the display tank. It has been suggested
that such bubbles represent an irritation to fish, corals
and other invertebrates and that they should be avoided. To
be honest, I am unsure from where the origin of this perception
came. However, it is untrue. Even the name is inaccurate
the prefix "micro" would refer to bubbles too small
The onslaught of bubbles from this oncoming wave should make
it apparent that
corals and coral reefs exist just fine with
the presence of air bubbles in the water.
Small bubbles are very common in tumultuous
reef environments, and areas where waves break are often dense
with both reef life and small bubbles. In addition, in tanks
and on reefs, many bubbles of various sizes, including true
"microbubbles" are produced by photosynthesis, and
this is especially the case in highly illuminated environments.
In my own aquaria, a constant rise of bubbles, especially
in the afternoon, are produced by various corals and algae
in even some of my less-illuminated systems. Larger bubbles
frequently get sucked into pump intakes, and are chopped up
to even smaller sizes and distributed throughout the tank.
I won't even begin to discuss the massive numbers of bubbles
produced by various surge devices. These water motion devices
have great benefits in aquaria, and even as anecdotal aquarium
observations, I have never seen anything disturbed, irritated,
or harmed by the rush of bubbles.
Potential: Relatively harmless.
Neither bubbles nor the lack of them in a tank is likely to
endanger the health or survival of organisms.
Distribution: A patchy, but
Myth 15: Concepts about Nitrification,
Stocking Orders, and the New Tank
I had owned Nilsen and Fossa's The Modern
Coral Reef Aquarium for several years before I noticed
one particular photo in that book that is exceptional. It
is a nice reef tank, but by no means what most would consider
to be a "show winner." However, it is unquestionably
a show winner, for it is a reef aquarium that grew solely
from live rock. If there is one universal answer to the question,
"What does it take to make a successful reef aquarium,"
the answer is patience.
For those who have not read one of the
threads stuck at the top of The Coral Forum, I offer this
revised version of that information. A tank begins without
populations of anything. Live rock typically forms the initial
basis of the biodiversity. Virtually everything is moderated
by bacteria and photosynthesis in our tanks. So live rock
is the substrate for these microbes and processes, and also
has a lot of other life on it. How much depends on a lot of
things. Mostly, marine animals and plants don't like to be
out of water for a day, much less the many days to sometimes
weeks that is common during live rock collection and shipping.
So, assuming that existing rock from a tank is not being used,
nor the well-treated aquacultured rock, most live rock is
either relatively free of anything alive, or has a few stragglers
and a whole lot of stuff dying or about to die because it
won't survive in aquariums. From the moment it is added to
the aquarium, a deficiency has begun that likely worsens over
time. Coralline algae, sponges, worms, crustaceans, echinoids,
bivalves, algae, chordates, and all manner of other taxa will
begin dying, many of which are within the rock and would never
be seen. All this occurs without mentioning the algae, cyanobacteria,
and bacteria, most of which is dead and will decompose, or
which will die and decompose. Life will return to some degree,
as we all have experienced, but not until death and more death
have occurred. However, this process is where it all begins.
Bacteria grow really fast, and so they
are able to grow to levels that are capable of taking up nitrogen
within a typical cycling time of a few weeks to a month (or
so) to levels where ammonium and nitrite are not measurable
by hobby test kits. Most people assume, wrongfully, that the
tank is now "cycled." However, the fact that ammonium
and nitrite are no longer easily measured does not in any
way imply that the tank is truly cycled, mature, stable, or
in any way able to easily support life in the form of new
additions. I will discuss this more in the passages below.
If one realizes the doubling time of many
bacteria, one would know that within a month, there should
exist a tank packed full of bacteria with no room for water.
That means something is killing or eating bacteria. It should
also be realized that if the tank has decomposition happening
at a rate high enough to spike ammonia off the scale of a
hobby test kit, there is a lot of food for bacteria that consume
this material, and far more than will be present when other
things stop dying off and decomposing. So, bacterial growth
may have caught up with the level of nitrogen being produced,
but things are still dying. An aquarist simply "tests
zero" for ammonia because there are enough bacteria present
to keep up with the nitrogen being released by the dying organisms.
It does not mean things are finished decomposing.
Now, if things are decomposing, they are
releasing more than ammonia. Guess what dead sponges release?
All of their sequestered toxic metabolites. Guess what else?
All their natural antibiotic compounds and these will prevent
some beneficial microbes from doing very well. The same occurs
with the algae, many other invertebrates, the cyanobacteria,
the dinoflagellates, and others. Suffice to say that this
death and decomposition is going to take a while to complete.
Through the initial periods, there will
be a tank packed with some kinds of bacteria, probably not
much of others. Eventually, the massive death slows and stops.
Now, what happens to all that biomass of bacteria without
a food source? They die. So, another cycle of decomposition
begins, and this back and forth process will continue for
a while until equilibrium is reached. I say equilibrium, but
that is a relative term since reproduction and mortality is
a constant process in our tanks, as are "mishaps"
and the relative size of the pendulum swing will depend on
the reproduction and mortality rates, and biomass of the organisms
involved. Still, the new swing of dying bacteria also has
antibiotics, toxins, and other substances released when they
die. But, the die-off is relatively slow, and is relative
to the loss of nutrients, and there is already a huge population
present. The result to the aquarist is that they never test
positive for significant levels of ammonia. "The water
Furthermore, denitrification is a slow
process. Yet, all these back and forth swings are happening...
every time, they get less and less, but they keep happening.
Eventually, they slow and stabilize. What's left? A tank with
limited denitrification and a whole lot of other stuff in
the water. Who comes to the rescue and thrives? The next fastest
growing groups... cyanobacteria, single-celled eukaryotic
algae, and other protists. Then, they do their little cycle
thing. And then come the turf algae. Turfs will soon get mowed
down by all the little amphipods that are suddenly springing
up because they have a food source and will reproduce rapidly.
Perhaps the aquarist has purchased some snails by now, and
maybe a fish. All too often, the fish dies, because while
it may not have ammonia to contend with, it has water filled
with chemicals we can't and don't test for. Beginning aquarists
may also have been too frugal with their purchase of important
equipment like lights and pumps, and may not have yet figured
out the important alkalinity test, so pH and O2
are probably swinging wildly at this point. Tests for phosphate
are also usually an afterthought, often purchased only when
algal biomass becomes uncontrolled.
No one wants their tank to look like this!
As a few more months pass, the algae successions
begin, and eventually there exists an algal biomass that handles
nitrogen along with the bacteria, and the aquarium keeper
has perhaps stopped adding fish for the time being because
they keep dying. Maybe during this time they started to visit
internet forums, read books, begin learning more, and get
the knack of the tank at least a little bit. They have, unfortunately,
probably added a smattering of "fix-it-quick" chemicals
(that probably didn't help any, either). Also, there are probably
two further scenarios; aquarists that are scared to add corals
in their "new tank of death" that would actually
help with the photosynthesis and nutrient uptake, or aquarists
that have packed in corals (most of which aren't tolerant
of the "tank of death" conditions). Equally common
are aquarists who stock their tank haphazardly without consideration
of whether or not the habitat present is suitable, but that
is a topic for another article. What may be relevant, however,
is the common pattern of stocking corals according to "hardiness"
over time. Initially, soft corals of the family Alcyoniidae
(leather corals), corallimorpharians (mushrooms) and zoanthids
are the first species to be purchased. The rationale for most
is that they plan to stock with easy corals and then "move
on to stony corals." The problem with the rationale,
seemingly logical though it may be, is that success of these
type species may make the tank even more incompatible for
the success of stony corals because they are typically superior
competitors (usually by secreting waterborne chemicals that
inhibit or kill the stony corals or by the capability of overgrowing
A host of "fix-it-quick" products exist to help
new aquarists through early troubled times.
About a year into the experience, the sand
bed is productive and has stratified, water quality is relatively
stable, and the aquarist has probably bought at least a few
more powerheads, understands water quality a bit, some corals,
coralline algae and other algae are photosynthesizing well,
and the tank is becoming "mature." That's usually
when fish stop dying and corals start to live and grow.
Ecologically speaking, this is successional
population dynamics. Its normal, and it happens when there
is a hurricane or a fire or other disturbance. In nature though,
there are pioneer species that are eventually replaced by
variably persistent "climax" communities. We usually
try and stock tanks immediately with climax species and find
it doesn't always work. The preceding passages illustrate
what good approximations reef aquariums are of mini-ecosystems.
Processes and events tend to happen much faster in tanks,
but this should be expected given the number of organisms
per unit area. Our "climax community" happens in
a couple of years rather than a couple of centuries, but it
After all the descriptions above, perhaps
the "myth" that is the focus of this article has
been forgotten. This section actually covers several myths:
the myth reflected by the statement "my tank is cycled"
or "my rock is cured," and the myth of the statement
"my water tests fine." The truth is that the tank
is never cycled, the rock is never cured, and water that "tests
fine" may be variably fine in terms of one or a few parameters
that may or may not be ultimately important for the survival
of the creatures we keep in aquaria. As a supplement to this
section, I offer some advice (and "advice" is not
something I am overly fond of providing because it tends to
be limiting to the viewpoint of the person giving it!). I
offer the words from a slide I have given in presentations
and am frequently requested to print or email after I have
shown that slide to a group. The following is how I would
suggest new tanks be initiated:
Potential: Always serious.
Mortalities early in the life of an aquarium can usually be
prevented. At the worst, these early misconceptions lead to
long-term problems with tanks, have medium-term direct effects,
and short-term mortality associated with them. Often, prevention
and understanding would alleviate the issues, and surely many
aquarists leave the hobby because of the many problems that
happen early on with new aquarium set-ups.
Distribution: Nearly universal.
Being patient with a new tank is almost an exercise in futility
that requires restraint. Generally, only those who have kept
reef aquariums prior to establishing a new one are likely
to take the steps required to ensure the best development
and success of new set-ups (and this is still comparatively
rare). Ultimately, the development of a tank by the actions
of an aquarist who "goes slow" will far outpace
those of aquarists who lack the patience and foresight.
years down the road, another condition might occur when
the system is too mature; this is sometimes called "old
tank syndrome." What happens in this situation
is that conditions have become somewhat stagnant, or
populations that are present are either limited by some
resource or are the only species capable of persisting
in the relatively non-fluctuating environment. This
happens in nature, too. The well-known example of a
forest fire reinvigorating the system is true. Equally
true examples occur on coral reefs where the intermediate
disturbance hypothesis is an experimentally favored
explanation of why coral reefs maintain very high diversity;
they are stable, but not too stable; require storms,
but not catastrophic ones; need predation, but not a
giant blanket of crown of thorns starfish; tolerate
mortality, but not mass coral bleaching or the near
total loss of key herbivores.
Myth 16: Corals will regrow over
dead areas of their skeleton.
This one is only partially a myth. Living
coral tissue may indeed grow back over skeleton that has been
exposed from partial mortality of the colony. However, there
is no real reason to suspect it will, and unless there are
small bits of tissue still living inside the apparently dead
skeletal corallites, the process is not as it may appear if
exposed areas are eventually recovered by living tissue.
Coral skeletons form part of the reef framework.
Once they die, for whatever reason, the skeletons are eroded
and become encrusted by other life, including other corals.
With partial mortality, living parts of a colony have no "attachment"
to their old vacant corallites, figuratively or literally.
It is not a preferred place for them to live and grow. The
coral tissue that remains alive will simply keep growing and
calcifying, upwards and outwards. Whether or not it grows
outward and recovers its own dead skeleton is mostly a matter
of how favorable it is to grow in that direction. Generally,
at the rate corals grow, the exposed skeleton will have long
been covered with other organisms vying for space before the
coral can grow over it. To retake that skeleton means that
some sort of competition will be required. In some cases,
it may simply be overgrowing coralline algae. But, if it means
overgrowing more competitive organisms, the remaining colony
may just grow off in other more energetically favorable directions.
In fact, this is more than likely what would happen.
Even if the coral does recover its own
dead skeleton, the polyps that grow over it will not take
up residence in the old corallites. They will create their
own new ones on top of the old ones. This type of regrowth
can be used as a proxy of environmental events that caused
partial mortality to a colony, and cores taken from old colonies
usually show a change in the primary axis of growth when the
skeletal core is examined in cross section.
As I stated in my first article in this
magazine, partial mortality of a colony is nothing to be concerned
about, and whether or not it ever becomes recovered with the
same coral's tissue is not really a concern so long as the
remaining polyps of a colony continues their growth somehow.
After all, none of us are really too concerned about the appearance
of all the calcium carbonate that lies underneath the living
veneer of tissue, either. Time heals all wounds, even in coral
Potential: Minimal in terms
of the health of the tank and the coral colony.
Distribution: patchy but
common statement and belief throughout aquarium circles.
Myth 17: You can never skim a tank
Yes, you can. Far too many works have dealt
with various aspects of protein skimming. I still feel there
is too little information on exactly what, how much, and how
effectively foam fractionation affects various components
of the water column of reef aquaria. For the most part, protein
skimmers are employed as water quality control devices to
maintain low levels of organic and some inorganic materials,
notably compounds containing nitrogen and phosphorous commonly
linked to degraded water quality not conducive to the growth
of many reef species such as corals. Whether or not they are
used secondarily for other questionably useful purposes such
as elimination of toxins or increasing oxygenation is another
matter. My point is that once nutrient levels are low and
conducive to a healthy aquarium, and until other secondarily
important aspects of protein skimming are experimentally validated
and quantified, any skimming over that required to maintain
low levels of organic and inorganic pollutants is overskimming.
Why? Because if the water is cleared of those things that
are detrimental, it is also likely to be equally cleared of
things that are beneficial. Given the now well-recognized
limitations of providing large amounts of food without a corresponding
decrease in water quality, skimming as little as possible
while maintaining the aforementioned high water quality is
only pragmatic. There is no advantage to a constantly stripped
water column in all but a very few specialized situations.
If I were asked what a solution might be,
I would propose the following. Use the most efficient skimmer
possible and one that is capable of maintaining high water
quality when used constantly. Assuming that they do provide
some amount of oxygenation, even if minimal, I would then
begin shutting off the skimmer during the day for a few hours
and measure tank condition visually and through testing for
several weeks. If water quality is maintained, I would increase
the number of hours the skimmer is off, and wait again, continuing
this process until the maximum number of hours is reached
where water quality and tank health remains the same without
the use of the skimmer. I would also opt for daylight discontinuance
since oxygen is less of a problem when photosynthesis is occurring,
and since most aquarists tend to feed fish and other products
like phytoplankton during the day. This way, residual foods
will not be removed for at least several hours. Some aquarists
may even find that they can discontinue skimmer usage entirely
(I think this likely, especially if activated carbon is employed).
Potential: Minimal to serious.
In the best cases, continuous skimming results in relatively
healthy tanks that are considered successful by most standards.
In the worst cases, organisms perish because of the lack of
available foods in the water column. In most cases, the results
are a "sterile" looking tank with little alive but
corals and coralline algae. Corals tend to appear weakened
and, for lack of a more accurate description, not robust.
Distribution: Extremely widespread.
There are many who employ alternate means of tank filtration,
and these are usually the same people who appreciate the obvious
differences in allowing more material to remain in the water
column without compromising water quality. Foam fractionation
use is both desirable and extremely widely employed, but as
with other things should be employed properly and with a judicious
Myth 18: My aquarium is a reef-crest
Sorry, but I very much doubt it. There
are many reef crests that are occasionally exposed to widely
variant conditions that range from onslaughts of rushing water
to absolute stillness. But, the typical fringing coastal,
atoll, or barrier reef crest is someplace humans don't usually
go or can't negotiate. Why? Because of the imminent threat
of serious personal injury. It only takes a very small wave
breaking over shallow corals to toss a human of considerable
weight like a leaf in the breeze. If one snorkels near a reef
crest, it is a constant physical negotiation to keep from
being smashed onto rocks and coral. A continuous body adjustment
as one is lifted up and down and side to side, consisting
of dexterous twists and brief sprints, is required to be in
this area. Even fish adjust their swimming behavior. As waves
approach and cross an area, small fish trying to maintain
their position or territory swim as hard as they can in one
direction, only to quickly stop as the wave passes. Other
fish take shelter in corals and rocks each time a wave passes.
While not on the reef crest, nearby stiff-bodied invertebrates
strain against the water forces, bent sideways every few seconds.
Softer bodied creatures, only existing in more protected nooks
alee of wave action are pummeled, and it amazes and fascinates
me that they survive the continuous unrelenting barrage of
wave action. On the reef crest itself, it is very unlikely
soft bodied sessile animals will exist. It is a very stressful,
violent, inhospitable and relentlessly tiring place to live.
Many aquarists think of reef crests as
being areas where many species of Acropora and small
polyped corals are found. In fact, only some species are found
there and the greatest diversity exists quite a bit deeper.
Staghorn corals are not found on most reef crests because
they would be shattered. Table corals are not found on reef
crests. They would be uprooted. Only the most robust growth
forms exist there, and colonies tend to be small. On many
reef crests, the force of water and the particles in it are
too erosive and abrasive to allow for any soft tissues to
exist, and corals are excluded. In such places, coralline
algae and perhaps encrusting Millepora are providing
the cover of the reef crest.
I have never seen a home aquarium where
I would feel physically in danger were I able to get inside
of it. I have never seen a pump that would toss me around
like a leaf. I have never seen any tank anywhere that in anyway
resembles a reef crest. Even small crafts with outboard engines
have difficulty maintaining a position anywhere near a reef
crest, and I suspect no one has an aquarium that would thwart
a 40 horsepower Johnson outboard. To provide conditions even
like those at five to ten meters depth in an aquarium would
still be quite a feat.
Potential: Minimal to serious.
In most cases, this myth is just a misconception of the nature
of both the reef crest and the tank. It won't do much harm.
However, if one perceives their aquarium to be a reasonable
facsimile of a reef crest and attempts to maintain animals
found on or collected from a reef crest, failure might be
Distribution: Fairly common,
especially among non-divers and enthusiasts of small-polyped
Myth 19: To propagate corals, one
should break or cut off a branch or section, and then apply
glue or affix the broken fragment to new substrate.
Coral propagation is really quite easy.
But, as I have said many times, these are not plants. Perhaps
the use of terms like "stalks" and "branches"
and "photosynthesis" confer this notion. But, one
should not "plant" corals with the healthy parts
up and the broken edge in the dirt, as though this was the
The goal in propagation is rapid attachment
with low mortality. Broken tissue is an injury, and injuries
are more prone to get infected. Reef substrate is covered
in biofilms and other microbes. The substrate also has reduced
oxygen and water flow, and is a site where other organisms
may engage in competitive or predatory behaviors. Finally,
injured tissue must undergo repair before growth is initiated.
The only helpful attribute of the "coral planting"
method is that the tissue edges are often sealed by cyanoacrylate
(super glue) that minimizes chances of infection. Epoxy putty,
however, confers much less of an advantage since the glue
is much less adhesive to mucus-covered tissue unless very
Providing the maximal amount of healthy
tissue against substrate encourages rapid attachment and reduces
the chances of infection and mortality. Placing cut edges
in water flow encourages healing and reduces the effects of
the detrimental attributes of substrate. Try it. I suspect
all the little "pine seedling" propagators out there
will soon change their ways.
The photo above left shows the "wrong way" to mount
corals. The photo above right shows the right way to mount
Potential: relatively minimal.
Corals are tolerant animals, in general, to fragmentation
and the majority of fragments even affixed in the wrong way
by "planting them" will probably survive. Some that
do not survive may have survived if affixed by a different
method more conducive to regeneration. The biggest potential
detriment is the increase in the time it takes for fragments
to reattach and in reduced growth potential.
Distribution: Extremely widespread.
Almost everyone, including those who propagate corals "professionally"
are mounting corals incorrectly.
Myth 20: The aquarium hobby has little
to no impact on reefs.
In some cases this is true, in some cases
this is untrue, and in most cases we just don't know what
our impact is. But, in some cases the aquarium trade has caused
significant declines in targeted species. The solution is
to be aware of what wild collected species are common, and
which are not, and to always purchase sustainably collected,
maricultured, or aquacultured stock when possible. I look
forward to covering this topic in much greater detail in a
Potential: Devastating to
some species, of minimal concern for others.
Distribution: This is a widespread
conception that is unfortunately based largely on supposition
and the hope that the statement is actually true.
This series has been a very incomplete
look at some of the more pervasive myths that are part of
the community of people keeping marine and reef aquaria. In
the first part of the series, I began with a somewhat lengthy
discussion of critical thinking and definitions of terms like
Being skeptical and critical in our assessment
of information in this hobby is imperative. The facts are
few, the opinions are many. The general level of understanding
is low, the data to support our observations scant, and what
persists is the all-to-common willingness to support our own
shortcomings of knowledge with those spoken and written by
those equally or sometimes more in the dark than ourselves.
We must listen more, think more, read more,
and speak less. At the very least, we should temper our enthusiasm
and excitement by prefacing our supposed truisms with really
helpful modifiers; could, should, might, probably, seems to,
in my observations, in my opinion, and looks like will more
credibly explain the immense number of unknown possibilities
that express themselves regularly to us through the windows
of our tanks. In time, we might even be able to say assuredly
"my water tests fine" and quantify how "my
tank never looked better."