PREPARING THE WELCOME FOR YOUR FISH
The only thing your aquarium now lacks to be complete is the arrival of its residents
Summon up your patience one last time, because the aquarium has yet to acquire
a perfect equilibrium: the plants must take root and bacteria must develop for the
Live rocks and the organisms they carry enhance the functioning
of a marine aquarium.
A gradual introduction
The minimum waiting period for a freshwater tank is 1 week, but 2 weeks is preferable.
In the case of a seawater tank, the wait can sometimes be as long as 4 weeks. If
you really cannot hold out that long, there are several ways of reducing this period.
As we have already stated, the aim of this waiting period is to allow bacteria to
develop and to avoid the presence of any toxic nitrogenous substances, so you can
speed up this development artificially. The first short cut is good oxygenation
- the bacteria need oxygen to respire and to transform the nitrogenous compounds
- the second is the introduction of bacteria. This can be achieved by adding sediment
or filtering material from another marine aquarium, sand, live rocks, or lyophilized
bacteria, which can be bought in specialist stores. However, this last solution
is not recommended, as it sometimes proves ineffective. Another alternative is to
become a breeder of bacteria, feeding them on organic matter that they would not
otherwise obtain in a tank that has been newly put into operation. The best menu
comprises one or two cooked mussels, cut into small pieces and placed in the aquarium,
with any leftovers being siphoned off a few days later.
Patience is required to achieve results as beautiful as
this in a marine aquarium.
Such measures can reduce the waiting period to 8-10 days. However, the nitrite
levels must always be measured regularly, and no fish must be put into the tank
until these levels have been stable at zero for around 1 week. Only then can you
switch on the aerator and UV sterilization (in marine tanks only).
Choice of fish
The choice of residents depends on the type of tank (community, regional, or
specialist), your tastes, and your budget. The number of species available on the
market is more than sufficient for most fishkeepers, especially novices. A quick
inspection of a few stores will give you a broad overview and enable you to make
a welljudged selection.
There are some rules, however, that must be respected if you are to avoid results
that are too often found: a "hold-all" aquarium, overpopulated with a motley collection
of species. It is best to choose a few species and keep them in groups - this is
possible for a great many species. Respect their natural behavior, as this increases
the probability of eventual reproduction. However, aggressive species that usually
live alone must obviously be kept as single specimens.
You can take advantage of all the different levels of the tank by combining free
swimmers with bottom- and surfacedwellers that can live in harmony.
Specialist stores offer a wide range of fish species, including
those suitable for novices.
There remains the problem of living space. The general rule, for small species,
is 1 cm of fish per liter of fresh water and 1 cm per 5 liters of sea water. The
table above presents some more precise calculations, but you must bear in mind the
maximum length that each species can attain in an aquarium.
ACQUISITION AND TRANSPORT
Obviously, a fish must have a clean bill of health when it is introduced into
an aquarium, and there are certain signs that indicate this. There is still a risk
of an unpleasant surprise, however, as some fish are carriers of diseases that only
come into the open once they are put into an aquarium.
The bag used for transporting fish must be left to float
for a while, to ensure that its temperature is the same as that of the tank.
Whether a fish comes from a store, a club, or a friend, it must always be scrutinized
carefully before acquiring it. This is why you must 276 not be in too much of a
rush and should get to know a storekeeper or join a club, to look and learn. When
you do finally introduce fish into the aquarium, you must adopt a particular strategy:
- It is best to populate the tank in one go, or at most in two, with a short
interval between, rather than introduce the fish one by one. A newcomer, by
definition, is perceived as an undesirable alien, which can give rise to conflicts
that sometimes result in its death.
- If you are obliged to stagger the introduction of the fish over a period
of time, it is best to start with smaller species and allow them to get accustomed
to their environment; in this way, they will not be so alarmed by the subsequent
arrival of bigger species.
Fish must be transported in airtight bags containing more
air than water.
Fish are quite easy to transport. Just put a small group into a closed plastic
bag containing one third water and two thirds atmospheric air. In the case of species
with spiny spokes, you can add a second plastic bag for protection. This system
is effective for a short trip, of one or two hours, depending on the external temperature.
After that, heat starts to be lost, although this effect can be reduced by surrounding
the plastic bag with material or paper and putting it in a polystyrene bag.
The bags used for transport must be insulated for long trips
to avoid any loss of heat.
Transferring your fish into an aquarium
The fish will be stressed when it is introduced into its new home, on account
of the transportation, the radical change of environment, and the difference in
water quality. To alleviate this stress, you must never introduce a fish directly
into a tank. Proceed in stages, allowing a minimum of 1-2 hours for the whole operation.
For the first 30 minutes, just let the bag containing the fish float in the aquarium
to make sure that the temperature is the same in both cases. Then open the bag and
put a little water from the aquarium inside. Repeat this operation several times
at regular intervals until the bag is full. You can then carefully transfer the
fish into its new environment.
If there are already fish in the aquarium, you must take two extra precautions
to increase the chances of the newcomers being accepted: distract the attention
of the other occupants by giving them food, and introduce the new arrivals in the
morning, before lighting up the tank. In any case, the new fish is likely to hide
for a while, and this is a completely normal attitude. When it reemerges will depend
on its nature, but it sometimes reappears after barely an hour. Some may take longer
to acclimatize, however.
It will soon grow accustomed to its new environment and the feeding schedule,
and will become completely integrated into the aquarium. If the fish is healthy
and you take all the necessary precautions, mishaps are very rare and the ecology
of the aquarium will not be upset.