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Growing reef corals is an endeavor for which there
are many wonderful paths to success. Last month I proffered so-called
"recipes" for feeding reef invertebrates, yet I am sure that
there is no single "best" recipe overall for success with
keeping aquarium denizens… only good ingredients. Its rather like
bread making: given to ponder, you might be amazed to think of the many
different varieties of bread in diverse cultures around the world, yet
there is the common thread of a few simple ingredients to most all of
them. I reckon that some aquarists with stressful jobs consider their
relaxing aquarium nearly the staff of life too that bread is in our
modern day! At any rate, whatever enjoyment it is that you derive from
keeping corals, I intend to help you insure it. To be successful as a reef aquarist, the literal
growth of one's charges is an inevitable and pleasant dilemma. Life
in stasis (without growth or decline) for coral is unlikely if possible
at all to achieve if you doing your job properly. Moreover, it should
be a great thrill for the aquatic gardener to bare witness to the fruit
of his or her labor as corals prosper. Inherent with the prosperity of
growing corals are new challenges for meeting the increasing demands of
providing sustenance and the very escalation of interspecific
aggression with cnidarians in the narrowing confines of the aquarium.
We need to plan for success when keeping corals and other reef
invertebrates. Before we can discuss how to manage growth, however, we
must first discover how to achieve it. The basic ingredients for growing reef corals
successfully are: appropriate light, food, and water flow. Please
remember, though, that all three ingredients depend on good water
quality and competent husbandry to make a successful recipe. Indeed,
good aquarium maintenance is the yeast that leavens our bread if we are
to continue with our food analogy for realizing success with reef
keeping. 1) The Delivery and Care of Reef Light and
Hardware Of the three main ingredients, lighting is the
most commonly addressed parameter in reef keeping. In popular
literature, it shadows the importance of proper food and water flow to
the extent that some aquarists seem to focus only on this parameter to
any significant extent. But again, success with aquarium corals is
dependant on all ingredients addressed in concert.
It would be fair to say that most popular corals
recommended to the average coral gardener are photosynthetic and depend
on proper illumination for the bulk of their sustenance. Symbiotic
species (with zooxanthellae) are generally easier for most aquarists to
care for in contrast to the aposymbiotic filter feeders. Most symbiotic
corals derive more than half of their nutrition from the products of
photosynthesis and the translocation of carbon. In suit, lighting
hardware is one of the most important decisions you will have to make
in an effort to grow reef invertebrates successfully. Choosing the
right lamps first depends upon making a list of targeted species for
the display. Identified corals can then be evaluated to make a proper
choice of lighting equipment to serve them. Otherwise, you will be
limited to selecting your future livestock around a hardware choice.
Buying lights before making the guest list of corals is really
counterintuitive. Once you have determined if you have a low,
medium, or high light needs and then have selected appropriate
hardware, good aquarium husbandry must support the effective delivery
of light… every day! Please consider that regardless of how well
suited your lamps may be above the water, all is for naught if the
penetration of light is persistently compromised by poor water clarity
(yellowing agents, turbidity, etc) or if the lenses and lamps are
routinely coated with dust and salt creep. The best and brightest lamps
in the world are merely a vehicle for funding the college tuition of
your local electric supplier's children if you do not consistently
export discolorants from the water and wipe the lighting hardware clean
twice monthly or better. Good protein skimming, proper use of chemical
filtration (small doses of media changed frequently), regular partial
water changes ("Dilution is the solution to pollution.") and
ozone are all helpful for maintaining optimal water clarity.
Another consideration is that the shock of a
sudden increase in light from a tardy address of water clarity can be
stressful and ultimately fatal to some corals. It is an underrated
cause of "bleaching" (the expulsion of pigmenting symbiotic
algae) and duress in many captive corals. You can imagine that it
wouldn't take much to cause such an event; consider the hectic
schedule that one has in the weeks before, during and after a holiday.
In concert with some neglectful oversights with the rotation of carbon
or tardy care of the protein skimmer, it is possible for a spell of 3
or more weeks to go by with little or no significant export of
discolorants from the water. After this expended period of time and the
escalating "yellowing" of aged water, a large water change
and exchange of fresh filter media may send system invertebrates into
light shock with suddenly improved water clarity! There are, in fact, many considerations for the
optimal illumination of corals. The details and nuances of this dynamic
were covered in the September 02 issue of Today's Fishkeeper for
suggested reading. There you will find a simple summary of lighting
limits and recommendations to help you easily navigate through the
blizzard of marketing that abound on this topic ("Lighting Reef
Invertebrates"). 2) Feeding corals… Not a Matter of
"If", but "What and How Often"
In last months issue, Oct 02 TF, I detailed
various elements of coral nutrition and recommendations for which
corals need to be fed what foods. In continuation, I should like to
proffer here basic advice on the proper application of foods for good
coral health. Let there be no doubt that most coral need to be fed
weekly if not daily. Nearly autotrophic corals are still not fully
self-sufficient in symbiosis with zooxanthellae and, if unfed, they
will starve to death in time… it just takes longer. Inadequate
nutrition is often the reason for so-called mysterious deaths in corals
after many "successful" months in captivity.
Good habits with food handling and preparation are
critical to deliver useful sustenance to your growing corals. Most are
not too inconvenient with due consideration. It is an ironic reality in
the everyday that aquarists far and wide succeed in understanding and
acquiring nutritionally appropriate foods for their invertebrates yet
fail to deliver them successfully. Two of the biggest obstacles in reef
husbandry with coral foods are perishability and prey size.
On the topic of food perishability, give similar
consideration to your fish food as you would to items fit for human
consumption. The most basic rule is freshness. The nutritive quality of
all foodstuffs degrade in time with critical vitamins waning first and
fast. Few if any foods keep well much past six months of age under the
best circumstances. Ideally, buy prepared foods in portions that can
easily be used in 2-4 months. Frozen foods and opened packages of dry
food should be discarded after 6 months. This aspect of good aquarium
husbandry is easily obeyed. However, proper storage of aquarium foods
is another matter altogether! Dry foods should be stored in a cool, dry
place in tightly sealed containers. They must although be protected
from extremes of temperature and humidity. Unfortunately, many food
containers are not so well designed that support from a zip-lock
plastic bag would not make a great difference. It is inevitable to want
to keep food containers nearby to the aquarium but few places close by
are suitable. Light from the aquarium, if not indirect room and window
light, quickly degrades the quality for foods stored in clear or
translucent packaging. Atop the hood or light canopy is a dreadful
place to keep a tin of coral or fish food. Furthermore, the fluctuating temperatures near the
top of the aquarium from day/night cycles of the lamps will also
shorten the shelf life of foodstuffs tremendously. This reality is
compounded by the humidity surrounding the aquarium which can quickly
lead to spoilage of freeze-dried, flake and pelleted fare that you
might not recognize for some time unless you snack on krill and fish
meal with your captives! An even worse place for food storage is
underneath the aquarium in an enclosed cabinet where the humidity can
build high enough that moss and orchids sprout spontaneously. The best
place for dry aquarium foods is simply in the refrigerator in a tightly
sealed container. When this is not convenient, keep only small portions
at room temperatures that can be used within weeks. Frozen foods should
be stored with like consideration in tightly sealed packages (zip-lock
bags are fine) and used within just a couple months. Any money saved on
buying foods in bulk that must be stored for extended periods of time
is lost on the degradation of food quality in time and the subsequent
compromise to your animal's health. A disregard of good food
handling is very ironic with corals in reef systems, which are some of
the most expensive aquarium displays in the hobby; its like feeding the
lowest grade kibble to a pedigreed dog.
Prey size is certainly the most underestimated
aspect of coral feeding and one of the most neglected dimensions of
reef aquarium husbandry at large. Corals that feed organismally
(particles) often have a very strict range of acceptable prey size that
can very down to the species level. Two Dendrophylliids, the yellow
scroll coral (Turbinaria reniformis or T. mesenterina) and the common
cup coral (T. peltata) are a prime example of drastically different
feeding strategies between like species in the same genus. Both can
occur in cup or scrolling morphologies and share grossly similar
traits. Yet, T. peltata has enormous polyps and depends heavily on
organismal feeding while the "yellow" related species feed
very little if at all organismally (it is not uncommon for aquarists to
observe that they rarely put their tiny polyps out). It is tantamount
to research a coral's likely needs for husbandry before purchasing
it. In most cases, form clearly follows function and
consideration of a coral's polyp shape and size will indicate
suitable sized prey. Large fleshy polyps like we see on cup corals
(Turbinaria peltata) and Elegant corals (Catalaphyllia
elegans) are better suited to capture and digest large zooplankton
and even minced chunks of meat of marine origin. On the contrary, the
tiny polyps of some leather corals like many Lobophytum species are
clearly unable to "grab" chunks of food from the water
column. Also, take to heart that tiny polyped octocorals usually do not
seem to respond to the sensation of large food particles nearby in the
drift or upon contact (target feeding). Their relative indifference to
organismal feeding is a clear indication that they derive their
nutrition largely by other means (predominantly from photosynthesis and
feeding by absorption). If you have any wonder if the food that you are
feeding your coral is appropriate… simply observe to see that
prey is being stung and digested. In some cases, excrement from the
coral is an unmistakable dark, stranded expulsion (as with hearty
feeding Fungiids) and proof positive that feeding was successful.
Beyond dry and frozen foods, liquid suspensions are offered in the market to aquarists too oft ill prepared to use them. With the recent popularity of bottled phytoplankton products brings the reminder of how the educated consumer if the best aquarist for our industry. When mentoring aquarists, I often refer to the "inappropriate and heavy" feeding of bottled coral food supplements with specific reference to phytoplankton substitutes. Some bottled phytoplankton products are very useful indeed but they are commonly misapplied and some may be lacking in instructions for proper application altogether. I have not personally conducted the studies on phytoplankton and bottled substitutes, but I have been enlightened by the reports of those that have. Notably, Dr. Rob Toonen has described that even the best bottled phytoplankton is effective in a very narrow range of application (whatever "best" is varies by species or nutritional composition for your individual purpose). The limitations of bottled food supplements have to do largely with "clotting" or coagulating of the matter as it ages, rendering the prey/product size too large for many of the fine polyped feeders. * Some recommendations for using liquid food/phytoplankton products: - They should ideally should be packaged, transported, sold and kept refrigerated throughout the entire chain of custody for the longest shelf life. Phytoplankton is especially sensitive to deviations and storage at room temperature. Spoilage can occur within days. - Like most foods, the shelf life of bottled
supplements is arguably 6 months at best after which time the efficacy
degrades dramatically (particle size increases significantly). Such
products are used best in 2-4 months. - With every application, the
liquid food sample should be whisked in an electric blender to reduce
particle size... hand shaken samples are largely ineffective.
Mechanical whisking is critical for bottled phytoplankton in
particular. It is on this last point that most aquarists fail
from lack of information. Most aquarists know not or will not commit to
this tedious application and erroneously feed more of the suspension
hoping for the best. In this manner, bottled supplements unfairly earn
their reputation as "pollution in a bottle". Some defenders
of the "no-blending" school of thought assert that the
undigested or oversized particles still degrade into useful dissolved
organics for corals to feed upon by absorption. I'll be the first
to say that I am not qualified or interested to test that theory. But
by the same line of logic, does that mean that small bits of dissolved
cheeseburger also have some potential use? What of rotting algae…
is that helpful just the same? I don't even want to form an opinion
on such matters. If we are talking about offering a suspension of
particles to an animal that feeds organismally (by whole
prey/particles), then I would rather not make or hear excuses about the
possible ancillary benefits of dissolved matter. The overwhelming
practical and anecdotal evidence on this matter also reminds us that
the abuse of liquid coral foods serves largely to fuel nuisance algae
growths at any rate. The best solution for aquarists in need of feeding
fine zoo- or phytoplankton but unable or unwilling to whisk prepared
liquid substitutes is to employ an upstream fishless refugium. Vessels
with course media and regular feeding can generate larger zooplankton
like amphipods and mysids. Sugar-fine sand or muddy substrates will
encourage copepods while surge-pounded seagrasses can proffer epiphytic
material and possibly phytoplankton. Dedicated aquarists and
researchers might set up food culturing stations instead for rotifers
or unicellular algae and drip feed their corals for optimal
feeding. There are indeed many options for feeding your
corals but always take heed of particle size and prey suitability. The
ultimate irony about the above mentioned misapplication of bottled
foods is that many of the targeted animals are unlikely to even eat
phytoplankton. The fact of the matter is that most of us have corals
that decidedly favor meaty fare (zooplankton). So unless you have a
herd of gorgonians or a gaggle of Nephtheids, I would resist dispensing
bottled phytoplankton in my tank like it was fertilizer. 3) Water
Flow… how much is enough? On this last point (ingredient for success), I
wish to offer you some simple guidelines on water flow as a foundation
for a future installment, having covered feeding and lighting in
specific address recently. Still… the summary for the successful
provision of water flow to corals is really a very simple matter. In
fact, water movement is perhaps the least controversial topic in reef
aquarium science. It is very difficult to have too much water flow
in most reef aquaria, but it is possible to dispense inadequate flow
improperly as to seem excessive. Most coral require strong random
turbulent or surge motion. For these corals, a laminar or linear flow
(one directional as we have from the spout of a power head) can be
quite dangerous and literally denude flesh from a coral ill adapted to
bathe in such a direct path. The exceptions to this rule are quite
conspicuous as with the sea fans and gorgonians. Fan-like corals
are morphologically adapted to live and feed in the brisk path of a
laminar flow and have grown into a flat plane to exploit such water
movement. For most other corals, however, it is safe and necessary to
change and deflect the path of water variably. The best application of water flow for most reef
displays (traditional mixed garden reefs) is a simple random turbulent
pattern with full time pumps or outlets (from a sump driven manifold)
pointed directly in opposition to each other. Thus, a dynamic and
random pattern of water flow is created throughout the tank by the
convergence of these energies. Surging water flow is arguably better
for many corals but not so much that it warrants the complicated and
unsightly employment of overhead dump or surge devices. The
interruption of water flow by wave timers and wave makers is equally
unnecessary and categorically less useful than the proper full time
employment of the harnessed pumps. Rest assured that the simple
creation of random turbulent flow from converging powerheads, for
example, will give you the most bang for your buck!
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