The most basic
requirement for life, especially if you are a fish!
This amazing
substance has more to it than meets the eye and much more in it than you can
see. Some of it is good for some fish, some of it is bad for some fish, some of
it is essential for fish and some of it is pure poison.
Those of you whose
kettles grow fur coats on the element will already be aware of the calcium and
magnesium salts in your hard water supply but not all water is like that and
not all fish enjoy it.
Water Cycle | Treatment | Aquarium Water | A fish IN water
All
water comes initially from evaporation from the
oceans. This evaporate is pure water. As it travels through the atmosphere it
picks up Carbon Dioxide and becomes Carbonic acid. Where the air is polluted it
picks up other stuff as well and in the worst cases it picks up Sulphur Dioxide
and becomes weak sulphuric acid or Acid Rain.
Most of us luckily
don't face this worst case scenario and most of us don't rely on rain water for
our direct supply. However the rain is still slightly acid so it tries to
dissolve whatever it falls on. If this happens to be calcium and/or magnesium
based rocks it dissolves quite a bit and becomes hard, the acid is neutralised
and overwhelmed so it becomes alkaline too.
If however the rock
is hard, granite or basalt for example, the rain dissolves very little and
remains acid. If this water then runs through peat or other organic, vegetable
soils it dissolves more acidic products like tannins, which colour it brown,
and humic acid. In these circumstances we get soft, acid water.
The kind of
countryside it passes through has its effects as well. Water coming from
intensively farmed land may pick up nitrate and phosphate from fertilisers, and
don't the algae in our tanks just love that!
It
may all sound fairly simple so far but it gets
worse (or better, depending on your point of view) because the water then
enters the domain of your local water authority. Their job, by the way, is to
produce water fit for human consumption, NOT fit to keep fish in. They filter
it, sterilise it, change the chemistry of it and add anti bacterial products to
it. As an example, here in Aberdeen our water comes from the River Dee which
rises in the granite Grampian mountains, runs through peat bogs and soil and at
times looks as clear a brown as a well brewed cup of tea. Ideal for rain-forest
fish? No. By the time it comes through my tap (faucet) it is crystal clear,
still very soft but ALKALINE! Soft acid water degrades water pipes so the
authority save themselves (and me) from having to replace lots of corroded
piping by reducing the corrosion through chemically altering the pH of the
water. They make sure I don't get a stomach bug or any other kind of bug, by
dosing the water with CHLORINE to kill bacteria. They stabilise the chlorine,
which comes out of solution fairly easily, with Ammonia to make CHLORAMINES so
that it will still be bug free after travelling through all those pipes. The
local dentists may get them to add FLUORINE to improve my teeth and some of the
NITRATES and PHOSPHATES from the farms are still there because 'safe' limits
are above zero.
Fish in the wild do
not have the 'benefits' of such concern. If they live in the rain-forests (or
the Dee) water is soft, acid and has no 'added extras' for their benefit.
If they live in
Central America or the Rift Valley Lakes of East Africa the water is hard,
alkaline but still additive free.
In
order to make your tap water fit for fish, you need at
least to get rid of the chlorine and chloramines. Chlorine attacks the delicate
gill membranes of the fish, making it difficult for them to breathe and it also
kills all the beneficial bacteria in your filter which stop your fish being
poisoned by their own wastes. You don’t want to suffocate and poison your fish!
Consider too their
natural habitat. While most freshwater fish will adapt to changes in water
conditions, some of them are better at it than others. Find out what the fish
you fancy is used to. If it has been bred locally from parents that have been
adapted to your local water then it might do fine in the stuff that comes out
of your tap. However it might have come from the wild, been kept or bred by an
enthusiast who altered their water to fit the fish, or it may be one of those
species that don't adapt very well. (I'm thinking of mollies for example. They
can actually adapt to living in full sea water but don't like soft acid water
AT ALL. Discus are still relatively close to their wild ancestors' preference
for soft, acid, Amazonian water) In these circumstances you need to treat your
water to make it suitable for the fish.
Soft acid water can
be made alkaline and hard by using commercially available buffers e.g. 'Proper
pH' from Aquarium Pharmaceuticals, hard, alkaline water can be softened and
acidified by filtering through aquarium peat. Advice on providing the
appropriate water conditions will be found in the Setting Up section of the
Tropical pages
Water
is your fish's complete habitat and life support system.
Being totally and continuously submerged has a few problems. Have you ever
stayed in the bath long enough to come out with wrinkled fingers? This is due
to OSMOTIC pressure. If two liquids, separated by a membrane (like skin) have
different densities then the less dense liquid will try to dilute the denser
one by penetrating the membrane. This happens to fish too. In fresh water the
fish's bodily fluids are denser than the surrounding water so water penetrates
the fish, trying to thin out these fluids. The fish responds by having very
efficient kidneys that produce lots of urine. Freshwater fish drink very little
too. Yes, fish do drink! In a marine environment the opposite is true. The
surrounding water is denser than the fish's fluids so the fish in effect dries
out. Marine fish drink lots and have kidneys that produce very concentrated,
salty urine. They also dispose of excess salts through their gills. This
osmotic pressure is why fish can be seriously stressed by water that is too
hard (dense) or soft (dilute) for their liking. It also affects fish eggs -
fish may breed in water which is too soft or too hard but the eggs may fail to
hatch.
Fish breathe the
water too. The only place water can pick up or lose gases is at the surface,
where it contacts the air. In stagnant water this can mean that only the
surface layer has any reasonable amount of oxygen in it. The same is true of
stagnant tanks or bowls. Air stone bubblers and filters improve the circulation
of water from the bottom of the tank to the surface and so help keep oxygen in
all levels of the water. Water temperature and density affect the gas levels
too. Warm water has less dissolved gases and denser water has lower levels too.
This, in part, is why marine tanks can sustain fewer fish than freshwater
tanks.
Fish are
'cold-blooded' i.e. their temperature is controlled by their environment, the
water they live in. For goldfish, this is normally anywhere between -10C to
20C. Their metabolism is capable of coping with these changes and can almost
shut down in cold conditions. Tropical fish, like bettas, don't have this
skill. Bettas kept in cold bowls (room temperature is cold when you're used to
25-30C) suffer and goldfish at 25C+ go into metabolic overdrive.
BE
NICE TO YOUR FISH. FIND OUT WHAT HOME WAS LIKE, THEN MAKE THEM FEEL AT HOME!