The Aquatic Environment
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this figure are absolutely fundamental,_ because almost any fish
which is kept under conditions given in the wrong sector for that fish
will almost invariably die sooner .or later because of that fact alone.;.
In other words the correct choice of salinity and temperature is so
basic to the fish’s well—being that it is vital forits survival.
environmental factors are not always quite as 'demanding as this,
and in this respectit is often quite possible to keep'a particular
type of fish for all of its normal life span in conditions which do
not suit it at all. For instance it is well known that fish grow to their
'
full adult size only if enough space is made available to them. There
is no reason at all to suppose that a stunted fish is any ‘unhappier’ or
suffers in any way in comparison with its fully grown counterpart,
but it is surely bad fishkeeping to provide insufficient space for a—fish
to achieve
expectations.
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Coldwater
Tropical
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Coldwater
Tropical
Fig. 1. The major types of aquatic environment
The usual test for the suitabili—ty of an environment is the readiness
with which a particular Species will reproduce itself in a given set of
_
conditions. As a general rulethis would seem to be a fair test, as
f long”as the characteriStics of that fish throughout its whole life are
taken into account and not merely those which predominate
at its
normal
time. _All waters in nature change their character—