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Marine - Saltwater Fish Articles |
Additional Resources:
Choosing the Right Aquarium:
Although it is important to choose an aquarium
that you think will look good in your living room, there are other
equally important considerations that affect the ongoing expense as
well as the health of the inhabitants.
One of the first choices you will face is whether to
purchase a glass or acrylic aquarium.
The differences are listed in the box below.
| Acrylic vs. Glass |
1. Acrylic is a better insulator than glass so a smaller heater
will work for the same sized aquarium and temperature fluctuations
happen slower. This is good for stability.
2. Acrylic is clearer than
glass. It actually lets 14% more light through than glass.
3. Acrylic can have a much
greater variety of shapes. Acrylic aquariums commonly
have rounded corners (rather than seams) and usually
have a more 'contemporary' look. Acrylic coffee tables
and even bubble tanks (like Captain Picard's aquarium on Star Trek).
4. A disadvantage of acrylic
is that it scratches much easier (be careful with inside
decorations) so special cleaning pads must be used. NEVER
use a brillo pad or a green pot scrubber on an acrylic
aquarium.
5. Perhaps the biggest disadvantage
of acrylic is the cost. Usually an acrylic aquarium will
cost 2 to 3 times what a similar sized glass aquarium
would. |
In general we have found that stability
of the environment is the most important aspect
of successful fish keeping. A lot of material has been written about
the ideal environment for various species of fish, which should be considered if you are planning on a species tank or know which fish you want to stock the aquarium with. The first consideration in general though, when choosing the equipment and the aquarium itself is the stabilitiy of the environment.
Size of The Aquarium:
Always choose the largest size
that fits your living room and your budget. In a marine
aquarium this is critical since the fish capacity is three to five times less
than a freshwater aquarium. The amount of oxygen available is determined mainly by the amount
of surface area the tank has since oxygen enters the water primarily at the
surface. Although aeration, with an air stone or a power head, seems like it
is directly adding oxygen to the water, most of the benefit comes from moving
water from the bottom of the aquarium to the surface where oxygen is exchanged
for carbon dioxide.
Water movement at the surface also increases oxygenation and will
generally increase the stocking capacity as well as the health of the fish.
Keep in mind that airstones and power-heads can (and generally will) fail at
some time or another so don't overstock an aquarium to the point that your
fish will die if the power goes out for a couple of hours! It is almost always
more desirable to have a few less fish that are colorful and healthy than to
push the limits of the tank and risk loosing some of your fish. Not only are
fish happier, but the maintenance is easier!
In general, although we have seen successful marine tanks that
are smaller, a 20 gallon is smallest size that we can recommend with 60 to
100 gallon tanks being much more desirable. The larger the aquarium, the greater
your chance of having a successful experience.
Back to Marine - Saltwater Fish
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Marine vs. Freshwater |
1. Specially formulated salt must be added to the marine aquarium
water. For salt we use Coralife or Instant Ocean, but any major
brand will work as well. Measured with a hydrometer, specific
gravity should be between 1.020 and 1.025. This is about 1/2
cup per gallon.
2. To keep the hardness
and calcium at higher levels, crushed coral and/or
aragonite should be used in a marine aquarium. Also,
the marine aquarium decorations can be coral skeletons,
shells, and other calcium containing objects.
3. The number
of fish that can be safely kept in a marine
aquarium is 1/3 to 1/5 that of freshwater,
or about 1 inch of fish for each 5 gallons
of aquarium water. |
Filters and Filtration:
There are three main types of
filtration for marine aquaria. Several other methods that
are more commonly used in reef systems can also be beneficial for fish only
systems and will also be mentioned here.
Biological Filtration:
This is the most important type of filtration for stability and
reduction of toxic wastes. In any biological environment there will be a production
of ammonia from normal respiration (fish release ammonia from their gills)
and the breakdown of wastes. Ammonia is toxic to fish and in nature is reduced
to nitrite by a bacteria called Nitrosonomas. Nitrite is also poisonous to
fish and is further broken down into nitrate by bacteria called Nitrobacter.
Nitrate is relatively harmless to fish but is a primary food for plants and
algae. Frequent water changes (say 10% every week or two) will control nitrate
levels.
Collectively the process of turning ammonia to nitrate is called
nitrification and is carried out in the presence of oxygen (aerobic conditions).
Denitrification is the process where nitrates are converted to nitrogen gas
in the absence of oxygen (anaerobic conditions). Denitrification is generally
not of concern to the marine aquarist unless the control of nitrates is desired
(See Reef Systems).
Under-gravel
filters are the most
common type of biological filter and work by pulling water down through a
bed of gravel at the bottom of the aquarium and pulling it up through the
uplift tubes. Reverse flow undergravel filters are set up to pull water from
the top of the aquarium by pushing it down the uplift tubes and up through
the gravel. Reverse flow filters are slightly more efficient since they take
water from the top of the aquarium which contains more oxygen.
Trickle-filters: Since
nitrification is more efficient in the presence of oxygen and the air
contains about 20% oxygen, as compared to about 7% oxygen for water, trickle
or wet/dry filters were developed in the 1980's which increased the efficiency
of biological filters dramatically. They place the bacterial growing
medium, filter balls with large surface areas, in the air (usually
outside the aquarium) and trickle the water to be filtered over them.
Many kinds, sizes, and shapes of trickle filters have been in use since
they were introduced. Although many trickle filters are external devices
used in a sump or hang on the back type of filters, several manufacturers
including the "Sea Clear System II" aquarium contain trickle
filters built into the back of the aquarium itself. The problem with
trickle filters is they usually produce high levels of nitrate, and
so are not often used in reef aquariums or other situations where nitrates
are undesireable. Read more
about nitrates here.
Live
Rock and Live Sand: These are used in
reef and marine systems as a biological filter. Live rock gives
the added bonus of having de-nitrifying bacteria deep inside
the rock to help remove nitrates. At least 2 inches of live sand should
be used if used exclusively for the biological filter, live rock
at 1.5 to 2.0 lbs. per gallon of water is usually recommended. Read
more about live rock and sand here.
Mechanical Filtration:
Mechanical filtration refers to the removal of particulate matter
from the aquarium. Filter types include:
Power
filters -forces the water through some
kind of floss.
Canisters -
with pleated cartridges act as mechanical filters. It should
be mentioned that diatomaceous earth filters, commonly available
in canister filters, can remove particles as small as 3 microns
in size which really 'polishes' the water. They can be used to
remove bacteria and algae blooms but generally clog after a short
period of time and should not be used on a continuous basis.
Under-gravel
filters -also act as mechanical filters
by trapping debris in the gravel. Mechanical filtration is good
for keeping the water clear and free of debris.
Chemical Filtration:
Chemical filters are used to remove things that are dissolved in the
water, and therefore cannot be removed by mechanical filters. They are
most useful in getting rid of the yellow color that often develops in
aquarium water over time.
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The most
common chemical filter is activated carbon,
used mostly in canister and power filters, it traps many substances
in it's minute pores. According to Martin
Moe in his book, The Marine Aquarium
Handbook, some of the substances removed
by activated carbon are: copper, ozone, chlorine, antibiotics,
some dissolved proteins and carbohydrates, iodine, mercury, cobalt,
iron, methylene blue (a common medication), malachite green (another
medication), sulfa drugs, organic dyes, and many other elements
and compounds.
Zeolites - Recently many other types of chemical filter
materials, called zeolites, have been developed to remove specific
compounds such as nitrate and phosphate. Generally a fish only marine
aquarium has no need of these types of filtration but can be used in
a mini-reef setup.
Other chemical media include:
- Ammo-chips for removing ammonia
- Nitra-zorb for removing nitrates
- Phos-zorb for removing phosphates
Nitrate and phosphate control is usually not needed in fish-only
aquariums unless the levels become very high, or there is a continual
problem with undesireable algae blooms. Mini-reef aquariums are
the most likely candidates for nitrate and phosphate removers
if other means of control don't work.
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Activated Carbon 1.6L |
Ammo-chips 12 oz. |
Nitra-zorb 7.4 oz. |
Phos-zorb 7.4 oz. |
**Note: Many of the
common aquarium medications including antibiotics are removed
by activated carbon and therefore should not be used when treating
the aquarium for disease.
Other filtration:
| Foam Fractionators / Protein Skimmers |
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Protein skimmers work by passing a large stream of
small bubbles through a column of aquarium water. Many different
substances (proteins) will adhere to the surface of the bubbles
and be removed from the water in the foam that bubbles from the
top.
Skimmers are beneficial because they remove
substances before they enter into the nitrification cycle which
reduces the production of nitrates and increases oxygenation of the aquarium water.
One of the drawbacks to skimmers is that they remove trace
elements and iodine which, if needed by any of the aquarium
inhabitants, must be replaced periodically. This is not usually
an issue in freshwater or saltwater aquariums, but both types can
benefit from the use of a protein skimmer.
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Berlin Protein Skimmer
This model cleverly increases the time the water is in contact
with the bubbles by doubling the length of the path the water
takes through the system.
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Ultraviolet sterilization
Ultraviolet sterilization works by passing water through
ultraviolet light. If the water is exposed long enough, at a high
enough concentration of light, bacteria, algae, and parasites can
be destroyed by the light. This is used extensively in ponds to
help with algae and green water. Treatment of diseases in aquariums
requires the most amount of exposure. The smallest units ( 8-9
watt) are made for tanks up to 50 gallons, while the larger 40
watt units are made for tanks up to 180 gallons. For pond applications,
8 watts per 1000 gallons is needed to kill off algae (green water)
but is not effective for disease control.
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This is a Rainbow Lifeguard model made for a pond application. The bulbs should be replaced about every 4-6 months. |
Ozone
Ozone can be passed through aquarium water to oxidize
all forms of organic pollutants and kill many of the same organisms
that ultraviolet radiation does. Commonly used in skimmers,
one should make certain the materials used are "ozone safe" and
that the water is passed through activated carbon before returning
it to the aquarium because any residual ozone in the water is extremely
toxic to the fish. Ozone is useful mainly in large public
aquariums to keep the water from coloring. |
 
AquaZone PLUS Ozonizers 100 |
| For purchasing
UV and ozone sterilizers try Marine
Depot |
Stocking Capacity of a Marine System:
The first thing you will probably need to know is how many fish
you can keep in a particular sized aquarium. The most common formula for the
amount of fish you can safely keep is based on the number of gallons of water
in the aquarium. For a marine aquarium the formula states that you can:
1. Keep 1 inch of fish for each
5 gallons of water.
This simple method doesn't take into account the surface area
of the water (for oxygenation), the filtration system (for removal of wastes),
and the general size of the fish. For instance, a fish that is 6 inches long
needs a lot more oxygen than 6 fish that are 1 inch long. In general you should
reduce the amount of fish if they are larger, and increase the amount of fish
if they are smaller. Another method is to:
2. Calculate the surface area of
the aquarium and divide by 48 to get the number of inches of
fish the aquarium can handle.
This method takes into account the aquarium
shape but not the filtration or the size of the fish. The second
formula favors aquariums that are shorter and wider i.e. not 'showtanks'
which are taller and skinnier.
In general the more complicated formulas are not worth the trouble
if you don't approach the maximum number of fish calculated by the above formulas.
Perhaps if anyone shows interest, we can write more on this later.
Community or Species Aquarium:
One of the funnest things about setting up an aquarium
is choosing the fish.
You should probably have some idea of what type of
fish you want to keep before stocking the tank to avoid problems
later. Do some research on each fish before adding them to your
aquarium.
Some fish are predatory or aggressive and
so should be kept either by themselves, or with other predatory species. For
instance a neat predatory aquarium can contain lionfish, eels, and groupers.
But smaller fish like damselfish and cardinals could quickly become lunch!
Some fish are slow feeders,
or are very shy and should be kept by themselves in a species tank. Examples
are shrimpfish and seahorses.
Note:
Aggressive species include many triggerfish, damsels (especially
as they get older) and some angelfish and groupers. Tangs
can become territorial and aggressive towards other Tangs
that are added later. To avoid this you can change the decorations
around before adding a new tang to an established aquarium.
Water Quality:
By most accounts marine systems need partial water changes on
a regular basis. The recommendation is to change about 20% per month. In deciding
how much and how often you wish to do water changes, keep in mind that for
stability, smaller water changes done more often are better than large water
changes done less often.
Note: This
is higher than what is recommended for freshwater!
Some of the reasons for water changes are to remove
nitrates, replenish trace elements, and to clean the gravel of
accumulated detritus which
are 'greyish piles of "mulm" that a accumulate in the
aquarium' according Julian Sprung and J.
Charles Delbeek in "The Reef Aquarium, Volume
1".
It is a good idea, although not absolutely necessary, to use water
that is filtered by either reverse osmosis, or deionization. Distilled water
(which essentially strips the water) can be used along with a good salt mix
to re-introduce essential trace elements, but it is much more resource intensive
than water filtered by reverse osmosis or deionization and is not generally
recommended.
Remember to add salt only to water that is replacing water that
has been siphoned out. Fresh water should be added to replace water that has
evaporated (which happens on a daily basis).
Any activated carbon you are using should be replaced monthly.
Feeding:
Make sure and find out any special feeding requirements your fish
may have before purchasing them and be sure you can provide them what they
need.
Some fish can have very specialized diets, especially Butterflyfish,
some Angelfish, Parrotfish, and Anthias. It is not uncommon to sell fish that
require coral polyps (called obligate coral feeders) or sponges in their diet.
Of course corals are far too expensive to buy as food but some specialty food
manufacturers include sponges in their 'angel formula' frozen food.
In any case get your fish to eat as many different kinds of food
as you can to ensure they are getting everything they need. Some fish are used
to eating all the time so they should be fed as often as is practical (always
small amounts at least once per day) while others, like eels can go for several
days without food.
The more you feed your fish the faster they will grow to their
maximum sizes.
1. Purchase as large an aquarium
as possible.
For filtration we recommend for a fish only aquarium an undergravel
filter for both stability and ease of maintenance.
Provide a minimum of 2 inches of some kind of crushed coral, aragonite,
or live sand for the substrate.
Buy a thermostatic heater, thermometer, hydrometer, a good salt
mix (at least enough to do 1 1/2 times your tank volume), and either a good
airpump or powerheads to power the undergravel filter.
If you are not using purified water (R/O, deionized, NOT distilled)
make sure you purchase some kind of a water conditioner that removes chlorine
unless you know there can be no chlorine added to the water. It is better to
be safe than sorry in this situation.
Purchase test kits for ammonia and nitrite (minimum).
Now is also a good time to buy any ornaments that meet your fancy.
2. Setup the aquarium.
Place it on a sturdy floor in a relatively draft free area.
Put the undergravel filter in place with either the airstones
or the powerheads in the uplift tubes.
Rinse the substrate material thoroughly before placing it on top
of the undergravel filter.
Mix the salt in the water either before or after placing it in
the aquarium. Make sure the specific gravity is between 1.020 and 1.025.
Note:
After this always mix the salt water before placing it in
the aquarium!
Place the heater, ornaments, thermometer,
and any lights in or on the aquarium.
3. The aquarium should be
kept 'running' for at least 24 hour.
This is so the water is oxygenated and the salt has been mixed
for at least 1 full day (24 hours).
Make sure the temperature is stabilized at an acceptable level
between 74 to 80 degrees.
5. Cycle the Aquarium and then add fish
4. Monitor the ammonia and
nitrite levels.
Test the ammonia and nitrite levels until they are both zero (or
very close to zero). The ammonia will peak first then drop off as the nitrite
peaks.
Don't add fish in the middle of this process. The damsel fish
have a good chance of surviving because the levels go up gradually instead
of all at once. After the levels drop to zero, add fish slowly
and keep an eye on the ammonia and nitrite levels to make sure the aquarium
is stable.
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