Creating a Natural Zaire River Tank
by Dave Ball
President of the Southern Colorado Aquarium Society
Aquarticles
One of the most rewarding areas facing the modern-day aquarium keeper is the challenge
of setting-up and maintaining a natural aquarium. When done properly this type of tank is
sure to provide hours of enjoyment for the owner. When I was first contemplating setting
up an aquarium with all live plants, simulating the Congo River was going to be the first
attempt. First, just a little bit updating in world history. The Republic of the Congo is
no longer, now it is the Republic of Zaire, and the Congo River changed to the Zaire
River. Keep this in mind when doing research or reading about fish from this area; most
books use Zaire instead of Congo when referring to river drainage systems of the region.
The main reason I chose to duplicate the West African river was because of my great
interest in cichlids and Synodontis catfish. Adding dither fish and live plants
created my dream tank come true.
Natural aquariums are not real hard to maintain, but they do have some requirements
that other tanks don't. The first of these is the golden rule of not putting a tank near a
window, as natural tanks will produce a little more algae. Sunlight can also overheat a
tank. Tank size is also very important; the smaller the tank, the faster the plants will
outgrow the tank and have to be pruned (I prefer not to trim plants unless absolutely
necessary. I'll explain later). Right now I'm using a 30 gallon tank (36 x 12 x 16) which
is barely big enough for this project. The longer and wider the tank is the better.
The other things to consider are lighting, light duration, gravel, gravel additives,
heating, fertilizer, number of plants, and types of plants. Then, once you've gotten that
far, you have to choose filtration and methods to control the nitrogen cycle. Add water
and fish that will feel at home in this type of environment, and then just sit back and
enjoy. Sounds easy doesn't it? It is when planned properly.
Lighting and substrata preparation are the two biggies in having a tank like this. A
freshwater natural tank has a relative called a "mini-reef" tank, which shares
similar needs for success. Varied lighting is a must. If you choose any plants with red in
them, you need bright light and a fluorescent tube that is a wide spectrum plant light or
a tube designed to produce light toward the red end of the light spectrum. Multiple lights
are a must with larger tanks. The reason is: the deeper the water the more light is
absorbed. I currently use 3 - 20 watt tubes. First is the Fritz "Bio-lux". It is
very bright, enhances color, and produces light toward the blue end of the spectrum, which
is also needed. The second is a Sylvania wide-spectrum plant light, it doesn't look as
bright but it gets the job done. Last is a Hagen "Power-Glo" currently
substituting for a Sylvania "Daylight". I like the latter because it adds to the
color of fish without taking anything away from the plants. All of the lights are of the
24'', 20 - 25 watt range. This tank has total of 65 watts, which is what's required for a
tank of this size. Remember a good rule of thumb is a minimum of 20 watts of bright light
per 10 gals of water. The exception is for those tanks that are deep; then things change.
Most good books on aquarium plants have charts to help determine a correct set-up.
A substratum is the next critical component to putting together a tank of this nature.
Gravel that is too coarse will not allow the plants to take hold and gravel that is too
small will prevent root growth. There are several types of gravel that can be used. I use
a mixture of "Tex-blast" blasting sand and small river pebble with natural
colors. This combination works well. I also use a gravel additive from Tetra products
called "Hilena Initial D" which includes plant fertilizer tablets in the
package. This product adds the needed iron and trace elements to the substrata to promote
plant root growth. I know it sounds like a commercial, but the stuff works. Iron is the
key element to a successful plant tank and the tablets help speed up root growth, which is
needed in the early stages.
Filtration is extremely important. I can't stress enough how vital proper filtration is
to make it all work. When using gravel additives, the undergravel filter is history. It
will just pull the additives through the plates and your water will take forever to clear.
Plants can be grown with an undergravel filter, I've done it with good success, but not
using one makes all the difference in the world. When using an undergravel, nutrients are
washed by the roots. The only way to prevent this is not to siphon around the plants when
cleaning the tank or to slow down the flow in the lift tubes, but the latter defeats the
purpose of the undergravel filter. Before continuing, I would like to state that the
system I'm telling you about is what works for me. Some of the things may or may not work
for you, but I've spent a lot of time experimenting and it is an on-going project for
future tanks.
Plants are an integral part of the nitrogen cycle. They go through the same process as
an unplanted tank, which involves ammonia, nitrates, and nitrite. The breakdown of matter
into acids and nitrifying bacteria is exactly the same. In a nutshell, decaying plant
leaves and fish waste go through the exact same natural process. This can make things a
little rough if you have poor filtration. Foam filters work well in natural tanks in
combination with outside power filters. The foam filter provides the biological end of the
system whereas the power or canister filter provides the mechanical removal of particulate
matter produced by the decaying plants. Plant decay is an unavoidable reality and just has
to be dealt with. I suggest using an outside filter that can turn the tank's total volume
of water over 3 to 5 times an hour. This may sound like a lot, but the particulate matter
has to be removed or the tank will have a pH crash like you wouldn't believe. This may
mean going through a filter bag or two each week, but it's worth it in the long run.
Remember efficient filtration is just one of the keys to success when growing healthy
plants.
Live plants incorporate two other processes that must be taken under consideration. The
first of these is photosynthesis where carbon dioxide is absorbed and oxygen is released
into the water. The second process is called respiration, which occurs when the tank is
dark. At this time, oxygen is absorbed and carbon dioxide is released. Photosynthesis
stops when the lights are off. The release of carbon dioxide back into the water is so low
that it doesn't affect the fishes, other than the nocturnal ones as their metabolisms slow
down at night, & so less oxygen is used.
Now we get to the next steps, which are water and plant selection. The water should be
as close to neutral as possible. Filtering through peat moss for the first six to eight
weeks will help keep things under control until the tank is stable. The choice of plants
is left up to what pleases the eye. Or, if you are a picky person like I am, they can be
selected to duplicate what is normally found in the region you are trying to recreate. The
choice is yours. I have mixed South American and West African plants together for the time
being, just to see how well the system works for various plants. My next natural display
will be a South American tank, and all the S.A. plants will be moved into it and replaced
with various African plants. Just remember: when setting up your tank, locate the plants
in accordance with their light requirements. Some plants like low light and do well at the
base of a plant that requires bright light. Try to select plants that have temperature
ranges that overlap - say approx. 5 degrees. This will allow you to have a wider variety.
Getting back to using peat moss as a way of controlling pH, peat produces natural water
softeners to help the plants out. I use charcoal in the filter instead of peat after the
tank is established because natural plant decay is taking care of it now. However, I still
do regular water changes. I'm trying to simulate a slow moving river with this tank, and
water is ever changing in a river.
Most of the plants that were selected for this tank are indigenous to West African
rivers, the ones from South America are varieties of sword plants that just happened to be
small enough for the foreground. The plants I chose came from several different families.
The first were members of the Anubias family. These plants are very hardy, come
in numerous shapes and sizes, and most prefer low to moderate light. Most of the 20 plus
species make excellent foreground or middle-ground plants. Currently there are 6 different
types used in this tank: A. nana, A. afzeli, A. lancolata, A. frazeri, A. congensis,
and A. coffeefolia.
The next plant I chose is the African Tiger Lotus (Nymphaea maculata). This is
one of the most beautiful plants around. The only problem I've had with it was due to a
fault on my part. When planting the bulb that it grows from, don't fertilize it or it will
grow out of control, sending many leaves to the surface blocking light the other plants
need. The end result is a forced pruning which will take away some of its beauty. If you
don't feed this one, you should only need one in a tank of 30 gallons or less. The two in
my tank are doing very well but should have been planted farther apart because of their
large leaves. The remainder of the plants consist of: Hairgrass (Elocharis sp.), Valisneria,
Red Hygrophila (Alternanthera rosaefolia), Water sprite, Wisteria, Sagittaria,
and Duckweed (anybody need some?).
Now comes the fun part - the fish. Remember that unless you've used some aged water
from an existing tank to start your nitrogen cycle, it's going to be 3-4 weeks before you
can add fish. Use a quality test kit to monitor the tank as the ammonia and nitrates rise
and fall. A few feeder goldfish can be used to get a tank going. After a while, the plants
will start helping this process. The only two things you don't want, as far as animals go,
are any fish that are vegetarians and snails. Both can do damage to the plants. Other than
that, whatever is appealing to the eye can be put in the tank. Just don't overcrowd it.
The fish that I selected for this tank all come from the Zaire River system. These
include: 7 - Congo Tetras (Phenacogrammus interuptus - 3 males & 4 females),
a Butterfly Fish (Pantodon buchholzi), a trio of Kribs (Pelvicachromis
pulcher), a pair of Steatocranus tinanti, a pair of Nanochromis nudiceps
and 5 species of Synodontis catfish (S. haugi, S. nigriventris, S. eupterus,
S. robertsi, and S. schoutedeni). Some of the catfish will have to be moved
when they get bigger, but are doing real well in this environment. One note: the
Upside-down Catfish is a schooling fish and does better in groups of three or more. Fish
should be added over a period of time and the water changed on a regular basis.
With all this in mind, an aquarium of this type, with or without fish, will be a
wonderful addition to almost any room in the house. Don't be afraid to try this. Just
remember that a little planning ahead of time will save you hours in the future and give
you more time to enjoy your creation.
Bibliography:
James, Barry. A Fishkeeper's Guide to Aquarium Plants, London: Salamander Books
Ltd., 1986 Wilson, Charles L. The World of Terrariums, New York: Jonathan David
Publishers, 1975
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