Fish in nature tend
to live in systems that receive regular water changes either through tidal,
current or rain/flood systems. Wastes produced by fish and other flora/fauna are
diluted or utilised by other organisms. In the aquarium the natural cycles are
missing or only partly present. Our job as fishkeepers is to replace the
missing sections of the cycles. In general this means replacing water.
The smaller the
container and the fewer cycles present, the more work we, the fishkeepers have
to do.
Bowls |Tanks |Marine tanks | Reef Tanks | Ponds
Bowls
and unfiltered small tanks. These require 50%
water changes weekly. The water should be de-chlorinated and conditioned
(normally one product) before being added to the tank or bowl. It should also
be left to stand so that the temperature is equalised. If the bowl or any of
the contents need cleaning it is best to remove 1/2 the water and the fish,
then clean the bowl and/or contents using the remaining water. Never use
untreated tap water as this contains chemicals like chlorine to kill off
biologically friendly as well as un-friendly bugs. Using 'Cycle' or some other
biological booster or culture will also enhance the missing bio cycles like the
nitrogen cycle.
Filtered
tanks. These generally require 25% partial water
changes every two to four week to dilute the end result pollutants, like
nitrate, produced by the filter
cycles. Again the water should be de-chlorinated and at tank
temperature. The old water removed from the tank should be used to clean filter
materials and other media to preserve the beneficial bacteria present on/in
these media. New water should also be chemically treated to match the water in
the tank. This is especially important where the tank houses fish that require
exact water conditions e.g. African Lake cichlids in hard, alkaline water or
Discus, South American Cichlids requiring soft, acid water. Marine fish
obviously need appropriately salty water. When syphoning old water from the
tank, make use of the vacuum effect of the syphon to remove debris from the
tank floor. Gravel cleaners are readily available which remove dirt from the
gravel bed while emptying the tank.
Fish
only marine systems are about the most intensive maintenance
tanks around. Because marine fish come from a very stable environment they need
very stable and clean conditions in their aquariums. 25% water changes every
two weeks are almost essential. Since marine tanks tend to be larger anyway,
you will need facilities to make up suitable quantities of fresh sea water for
these changes at least 24 hours before you do your maintenance.
Live
rock and live sand marine systems are about the
closest aquarists have come to complete balanced eco-system aquaria. The many
and varied microscopic life-forms on and in the rocks and sand complete the
nitrogen cycle by releasing free nitrogen from nitrates and also fully cycle
other chemical chains. Water changes should be kept to a minimum but
maintenance is still required. Pure water evaporates from the tank and must be
replaced to maintain the correct salinity. Calcium and other elements are
removed from the water to help build the structure of some invertebrates and
algae. These 'trace' elements must be replaced, some on a daily basis.
Ponds
will probably require less in the way of water
changes. Outdoor planted ponds can be left untouched for months providing a
natural balance of stock is maintained. This is however very low compared to
most ornamental fish ponds. Even so, 10-20% water changes every 3-6 months may
be all that is required.