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Being
a member of the African Cichlid List I have a first hand view of
the problems and issues that really interest fellow hobbyists,
especially the ones keeping cichlids from the African Rift Lakes. I
have repeatedly come across hobbyists complaining that one species
bullied other species in their tanks or even killed them (which is
also common in tanks housing their New World cousins). Moreover,
many newcomers ask the question "which species are compatible
with the one I like or keep". Since
there has been some ongoing discussion on mixing cichlids and the
fear of side effects usually following the wrong decisions (= dead
fish), I would like to make some points which may
help fellow hobbyists understand some of
the key issues.
What
is the term compatible
fish refer to ??
Normally,
we use this term to speak about fish that need the same water
chemistry (pH, GH, KH) and physicochemical characteristics
(temperature, conductivity, osmolarity etc.). I am sure you know the
rule of thumb : "do not mix American with African cichlids
because of their different water requirements". So most people
know that Discus thrive at a pH lower than 6.8, almost distilled
water and frequent water changes, American cichlids usually prefer a
neutral or slightly alkaline water (pH 7-7.5) and are not very
particular on the salt content of their water and, finally, cichlids
from the African Rift Lakes (Malawi, Tanganyika and Victoria)
require alkaline water (pH 7.8 - 9.0; depending on the Lake) and a
mixture of salts in it. Most newcomers don't even go that far; shape
and color are the primary (if not only) concern. And then, problems
start. Fish get bullied, constantly chased, hide behind the filters,
refrain from eating, get sick or just get killed by their tankmates.
Although a fight resulting in a wounded or even killed fish in a
tank is something that can't be completely avoided, losing a fish
every day is unnatural and is - almost exclusively - a sign of
incompatibility.
If
water parameters was all there is to it, then "compatibility"
would be a very easy issue to be addressed and everybody would be
able to cope with it. Unfortunately, "Compatibility",
as a term, is a much broader
parameter and
covers many more issues than just water chemistry. It is because of
this reason that most hobbyists run into troubles after a short
while. I will just list (and shortly explain) a few parameters that
I have personally known to play a key role in the well being of our
aquatic pets. I will even go as far as give some examples from my
own experience with the African cichlids of Lake Malawi which
definitely allow very little space for wrong decisions as far as
tankmates are concerned.
Dietary
needs. Species
are classified as being omnivores,
piscivores, herbivores, carnivores, insectivores
etc. This has to do with their primary feeding source and should
always be taken into account. Of course, in nature, fish will feed
on what is available or easier to get but they are usually
specialized on chasing, grabbing, grazing, eating and metabolizing a
specific kind of food - on which they usually feed. Feeding the
wrong food in our tanks can lead to all sort of problems, among them
the - usually fatal
- Malawi bloat (which doesn't affect Malawi cichlids only). The
intestine of all species is suited to the food they should take and
can't "use" other type of foods efficiently. This has to
do with the length and special construction of the intestine walls
and can't be adapted to the wrong food. Herbivores for example, are
accustomed to the high cellulose content of algae and can fully
utilize it with their special mouths, teeth, stomach and longer
intestines. A piscivore, fed on the same diet will manage to get
only a fraction of the nutrients from it, and in most cases, basic
elements needed for its growth will not be present in adequate
quantities. In short, all species can take the wrong kind of food
every now and then but they shouldn't be fed constantly on the wrong
type of it.
On
top of that, fish eating at the surface of the water prefer food in
flakes, bottom feeders prefer sinking pellets or tablets, midwater
feeders prefer slowly sinking pellets etc.
Another
point is fish size. It is evident that you
can't feed your foot - long Astronotus
ocellatsus (commonly known as
Oscar) with baby growth food or your Barbus sp. (e.g. tiger barbs)
with big size cichlid pellets. If you feed one type of food, some
fish will be underfed while others will be overfed.
Assuming
you have a tank filled with fish which are incompatible as far as
their dietary needs are concerned, you may have to use two or more
sizes from every food they need. Surely, it would be easier if this
kind of compatibility was checked when you were selecting them,
isn't it? A classic example of keeping (dietary) incompatible
species together is the common African Cichlid tank where usually mbuna
(herbivores) are kept with Malawi Haps (a very common species: Sciaenochromis
fryeri), or even piscivores (Nimbochromis
venustus is very often seen in such
tanks).
Fish
temperament Some
species are listed as "aggressive"
in the literature and this is a warning that every hobbyist should
take into account when selecting fish for his / her tank. Aggressive
means that the fish will usually form a territory (mostly the males)
and will defend it against all intruders. He will chase, nip, wound
or kill any fish that doesn't seem to get this message. This
behavior doesn't mean that the fish is "bad" since it is
part of its natural behavior (usually fierce competition for food or
territories in their natural habitat). Keeping such species in small
tanks is the perfect way to create a battlefield until the problem
is solved by the fish itself (by killing most fish in the
tank).
Tankmates
should be selected among species of the same size and temperament,
while ample space and hiding places are a must. In such an
environment, full of compatible fish, a dynamic equilibrium will
soon be reached and the tank will go on for years without any
serious problem. If I were to give some examples of aggressive
species I would name the Melanochromis
genus (most notably Melanochromis
auratus and chipokae)
and some American cichlids (Astronotus
ocellatus, Cichlasoma
nicaraguensis etc). These are
species known to be really aggressive. However, as you can see
elsewhere in this site, I have kept 5 Melanochromis
chipokae males, 13 Melanochromis
chipokae females, a colony of 10 Melanochromis
auratus (1 male and 9 females)
along with a Pseudotropheus lombardoi
pair in the same tank for three years
without any serious problems. Fierce fights were observed every now
and then but after a while everything was peaceful again.
It
should be noted that the listing of a particular species as
"peaceful for an African" is only a general remark
which describes the average behavior of this particular fish.
Individuals can greatly vary (as with all animal species). I
personally own a male Cyrtocara moorii which is the
hyperdominant fish in my non-mbuna tank (till now) and has shown to
be very aggressive at times. If you check your books you will see
that this was supposed to be a relatively peaceful species - well,
mine is not. |
