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On
the Rocks?
Of course I don’t really mean Aquarium with ice cubes. The word
“rocks” should be taken literally in this case. I merely intend to give some
guidelines and advice to those aquarists who, like me, keep cichlids from the
African Rift Lakes. African Rift lakes include lake Malawi, Tanganyika and
Victoria as well as some smaller lakes in the same area. The information
included in this article is based partly on books I have read but mostly
originates from my experience with these species (mostly Malawi mbuna and Haps).
I have kept them for 5 years now and tried every possible combination in
aquascaping. Strangely enough, no matter what the aquascape was the Africans did
well – really hardy fish if one keeps the basic rules. However, there is only
one aquascape which revealed their true behavior, their natural instincts,
increased spawning frequency, reduced aggression and finally let these fish
thrive. To cut a long story short, the best aquascape for these species is plain
sand (too much sand) and rocks (too many rocks). If one follows this simple
aquascape then success is almost guaranteed. I assume that the fishkeeper knows
everything about water chemistry, water changes and feeding habits for these
species and his only worry is the perfect aquascape for them.
Why
rocks and sand?
Firstly, because this is their natural biotope. As I always proclaim,
fishkeeping is both an art and a science. It is always stupid to
neglect nature’s lessons. These species evolved in this specific environment
for millions of years and everything they do, even the way they look, is adapted
to this environment. Keeping them in anything else than rocks and sand is
already “unnatural” by definition. Once I met a hobbyist who kept a Sciaenochromis
fryeri (a fish with an intense blue color) in a tank with a purple
(fluorescent?) gravel. Why? The answer was “Because it makes a good
contrast”. Forgive me for saying that, but if this is your idea about
fishkeeping you shouldn’t spend any more of your time reading this article.
All of us know that the idea behind the coloration of any living creature is
mainly to adapt to its background, to become less visible to its enemies
(predators) or to make the predator invisible to its pray. Take a look at the
photo of the sub adult female Nimbochromis livingstoni in my tank. You
can barely see where the rock stops and the fish starts. Since this particular
species is primarily an ambush predator you understand that rocks and sand is of
paramount importance to it.
A
female Nimbochromis livingstoni aged one year is making use of the
surrounding rocks to become invisible. The fish may stay motionless for some
time showing its normal behavior.
This
is the idea behind it. No blue creature would survive for 5 million years over a
bright pink bottom unless it was the largest, most aggressive predator around.
Still it would probably starve to death since it would be visible from miles
away. Secondly, these fish use these two elements (rocks and sand) all the time
for their everyday needs. Malawi rock dwelling fish (mbuna), their Victorian
counterparts and the Tropheus genus from lake Tanganyika are classic
examples, which use the huge rocks to eat algae (or invertebrates / crustaceans
that live in it), to hide or to spawn. In short, they spend their whole lives
next to a rock. Keeping them in an aquarium without rocks is simply unnatural.
Haps on the other hand use the sand to create their spawning pits, clean their
gills, there is evidence that they even use it to digest their food. This is an
element of their surrounding, which is essential for their well being – it is
not an accessory, not if you are dead serious about keeping these species happy.
Even if we examine the aesthetics of this combination, nothing beats it. It is a
pale, neutral combination, which brings out the colors of even the dullest fish.
It will not distract the eye (as colorful plants will) from the fish itself,
thus making your precious fish the point of interest. It also creates the
impression of the “natural” environment to the spectator. It makes your tank
a “miniature” of the lake. I hope you will agree with the principle that
rocks and sand is all the African cichlids from the Rift Lakes will ever need.
Then we have to discuss the various issues that the fishkeeper has to pay
attention to in order to create a trouble free environment.
Collecting
the sand.
You can use almost any kind of sand but I strongly recommend the sand you will
collect yourself – unless you need too much of it. You can use river or lake
sand but the best is sand collected from a nearby beach. Of course the sand
should be cleared from any stones, papers, pieces of wood or plastic, glass etc.
You may use a sieve to collect the fine sand leaving all other particles on the
sieve. “White” sand is the best option. Usually you should avoid gravel with
light color since this doesn’t allow the fish to feel comfortable. However,
you shouldn’t worry about the sand because it will look considerably darker in
your tank – when wet.
Collecting
the rocks.
With rocks and stones you should pay attention to collect real rocks. Yes, it
may sound a paradox but sometimes you may end up with pieces of marble or cement
deposited there by humans. The best rocks are the ones, which have no sharp
edges to avoid fish wounds. Sometimes your fish may need to scratch on the rocks
because of the presence of protozoans in their gills. In this case, sharp edges
may scratch their protective slim coat, which is the first step for all sorts of
infections. You should collect
rocks of various sizes but you should also take care to collect both round and
flat rocks. A little planning beforehand will help you to get what you need.
Make a drawing of what you intend to build and take a ruler or other measuring
device with you. You must take into account the dimensions of your tank.
Collecting a beautiful huge flat stone is pointless if it won’t fit in your 20
gallon tank. Another thing to consider is the weight of the rocks. On average
you must calculate that a rock is 2.5 times heavier than water. If you have a
household bucket with volume indications you can fill it with water, dip the
rock in, take it out and see how many liters of water are missing. You then
multiply this number by 2.5 and you have the weight of the rock (in Kg). You
should avoid any rock which has plant matter attached on it (algae or other
plants). If you plan to have a well-lighted tank the color of the rocks
doesn’t really matter because they will be soon covered with algae. If you
will have a normally lighted tank you should avoid the white stones (or the ones
with a light color) and opt for the dark ones. The best colors are black, dark
gray, dark green and dark brown stones. These colors make a natural contrast
with the light color of the sand. The best stones can be found in the water or
at the waterline, since these stones are washed by water and there are
absolutely no sharp edges. Some stones contain a large metal content and they
will leak in your tank. This may introduce heavy metals (iron, lead, copper
etc.) in your tank something to be avoided at any cost. Heavy metal poisoning is
always fatal to fish and usually it won’t have any warning symptoms. In order
to make sure that this will not happen you should check the rocks on the spot.
Choose any “vein” with a metallic color (like rusty iron) and add some drops
of a weak acid (use a lemon or vinegar). If you observe any fizzling or see any
small bubbles formed then this rock will definitely leak in your tank, leave it
there and choose another one.
Cleaning the sand
and the rocks. You will have
to use buckets and plenty of water. Don’t rush this procedure; take your time.
The more time you spend cleaning the sand at this stage the fewer problems you
will have later on. Otherwise you will have a cloudy tank, all dust will settle
on the bottom and will then reappear every time your fish stir the sand. It may
also clog your filter (especially sponge filters). Use many changes of water
(while stirring the sand with your hand) until the water comes out clear. With
rocks you will have one step more. Before washing them you will have to scrub
them with a toothbrush or a bath brush to remove any particles from their
surface. Then you will wash them (separately from the sand) until the water
comes out clear. When you see that the water comes out of your buckets clear it
is time to move on. After the final washing you will have to disinfect your sand
and the stoes. You can either boil or chemically disinfect them. I do not
recommend boiling sand and rocks because some times the rock may break
(especially if air is trapped in a cavity). I prefer chemical disinfection with
household chlorine. I use a 10% solution for both rocks and sand. I leave the
chlorine solution for 2 hours and then I wash it with plenty of water. You must
only stop when there is no more chlorine smell and there is no foam formed. Then
you will fill your bucket with water, add 10 times the recommended dose of
dechlorinator and leave it there for an additional 15 minutes (stir the sand at
this point). After that, remove the water and let the sand and stone to dry
completely. You should store them in closed containers until you need them. I
use to store them in old travel bags wrapped in clean old clothes.
Placing the rocks in
the aquarium
The
first thing
to remember is to add the rocks first (not the sand). Always place a piece of
styrofoam on the bottom of your tank and place the rocks on them. The weight of
the rocks and the sand will keep the Styrofoam in place; there is no reason to
glue it on the bottom with silicone. Add some large rocks at the bottom row
since the sand will cover completely small stones. Use your imagination at this
point. Carefully select the stones and form steady piles.
Creating
caves of variable size is
very important. You must keep in mind that tiny fishes as well as adult ones
will use these caves. The fry released in the tank during the first stage of
their lives will use the caves. In this case the caves should be really tiny so
the fry will fit in but larger fish won’t. This will dramatically increase the
survival rate of the fry. As you can see in the photo, some fry will make it
even in a large tank (320 gal) of predators (Malawi haps).
A
young Nyassachromis boadzulu only gets out of its small refugee to take
some food particles. It has to be very careful though. If it goes a bit further,
it will be eaten on the spot.
The
caves will be also used by pray trying to escape its predator; this fish can be
of any size so you need many sizes of caves. Submissive males will also use them
to escape the harassing of the dominant ones. Carrying females as well as sick
or wounded fish will also use them as a shelter. Finally they will be used as a
day home for nocturnal species like catfishes (plecos, loaches and Synodontis
species – see photo).
A
Synodontis decorus in its usual day siesta. Being quite territorial the
catfish will not allow any other fish enter its shelter. As the catfish becomes
more acclimatized, it will leave its shelter even in daylight to search for
food.
continued in next page
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