Three Strikes
by Tony Dawe
London Aquaria Society, Ontario, Canada. April 2001
Aquarticles
Over time, each species of fish has evolved to fit into the environment in which it is
found. Because the species has evolved over thousands of years to a particular
environment, that environment can be termed to be “the optimum environment”.
As fish keepers, when we know a species' optimum environment, we can then modify an
aquarium’s set-up to most closely suit that species. Some examples of possible
modifications include the size of the tank, the amount or colour temperature of the light,
the pH, the water’s hardness, and temperature, to name a few. The amount of
difference between a fish’s native optimum environment and the aquarium in which they
are to be housed can be the difference between that fish’s ability to thrive or to
just survive.
When an individual fish is wild-caught or only one or two generations removed from
being wild-caught, the more important it is that the captive environment matches as
closely as possible to the fish’s optimum environment. Some species of fish can
thrive for years when only one or two of the environmental factors is changed. Some
fish-keepers, for example, keep discus in a hard, alkaline water, while others might keep
angelfish routinely at 70-72 degrees F. instead of the preferred 78-80 degrees F., and
often, in these conditions, the fish will live and even thrive for years.
The purpose of this article is to examine the cumulative effects of stress on a fish
when it is kept in an improper environment. A fish which prefers soft water can be raised
in hard water; however, if the temperature is also too low, or if the food quality is poor
as well, then it takes much less additional stress to kill the fish, whereas in its
optimum environment, the fish would easily be able to shrug off the burden and survive.
Often, when a fish species is kept in an optimal environment, it will live much longer, be
more robust, colourful and active than a fish kept in a poorer quality environment.
Take, for example, angelfish. They prefer a warm, soft water environment, with slow
water movement, an acidic pH, and top-quality foods. If provided with all of these
factors, the fish are much more resistant to disease and stress, and at the same time,
more resilient in recovery when problems do arise. Should the angels be kept at cooler
temperatures or in a hard water aquarium all the time, they are more likely to suffer from
an additional factor like a sudden temperature drop or an unexpected long gap between
feedings.
The more differences that exist between the optimum environment of a species and the
aquarium they live in, the more stress becomes piled on. There are people who brag about
not needing to perform water changes because their tank is “crystal clear, and
therefore, clean." Many of those people don’t realise that they are
creating a nasty time bomb - suddenly, there is a temperature drop due to heater failure,
or a fish becomes singled out as the target of a more aggressive fish’s bullying and
becomes sick - this scenario can often result in a catastophic wipe-out of the tank’s
inhabitants. The last straw CAN break the camel’s back.
If angelfish are kept in poor water conditions and fed poor foods, they not only have a
shorter life span, but are also weaker. Add in other failures to meet the optimum
environment’s standard such as maintaining a low water temperature, and/or harassment
from other fish, or any other environmental factor, and these fish may soon be dying or
dead. Disease will spread faster, cutting down precious time to diagnose and treat the
problem, and the disease becomes more likely to be lethal.
When a novice fish-keeper sees the first sign of disease, he will often medicate
immediately to treat the disease. Experienced fish-keepers have learned that sometimes the
environment alone can make a fish sick, and that adding medicine to a poor environment
only makes the problem worse.
If your fish suddenly become sick, sluggish, or “go off their food”, perhaps
the fish’s environment should be the first possible cause to be carefully examined.
Frequently, if environmental problems are first corrected, the fish may then heal
themselves, and if the correction to conditions is quite enough to enable the fish to heal
themselves, then they will certainly respond more favorably and quickly when medication is
required.
By watching your fish on a daily basis, the fish-keeper gains a better understanding
and perspective of what the fish’s true natural behavior should be, and then
environmental problems can be detected early and therefore, corrected early before a
fish’s health has deteriorated beyond the point of no return.
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