How Long Do You Wait Before Adding Fish?
- and other tips
by Bill "Pegasus NZ" of New Zealand
Opinions vary so much on this subject that it is hard to give a reasonable answer. The
Americans for instance have what is known as "cycling", which is the period of
time a tank has to remain empty of fish until the good bacteria have established
themselves and are controlling the conditions of the water in the tank. Most aquarists in
the States recommend a six week waiting period using what they call a "fishless
cycle." In order for the good bacteria to build up (starting the nitrogen
cycle), a source of ammonia is needed for them to feed on. When using this fishless cycle
it is recommended that you add daily doses of pure ammonia to the tank for the bacteria to
feed on, which is needed for the nitrogen cycle to actually start working.
There is also another method used by the aquarists in the States that allows one to
avoid this long waiting period. In this method the system is more in line with the methods
we adopted many years ago, and it is these methods that we will be mainly be concentrating
I would however like to point out that I personally have never used the "Fishless
Cycle" method, and never shall. Having to sit and watch an empty tank for weeks on
end is not my idea of a pleasurable hobby, so any references to "Cycle" in the
following article shall mean the "Nitrogen Cycle", which in simple terms means
the time that the system will take to establish a working biological filtration system.
The reason you have to wait is because the water needs to become established with a
good biological filtration system that only the good bacteria can provide. Personally I
find this length of waiting period unnecessary, as the work, time, and cost of the
exercise would certainly drive most enthusiasts away from the hobby.
I'm probably an old 'fuddy duddy' having only been involved with fish
keeping/breeding/retail/wholesale/ and supply since I was eighteen. (I'm now 62). I've
been reading just about anything of interest since I joined various tropical fish forums,
and this 'Cycling' thing seems to be a major topic. This is a 'new word' in fishkeeping to
me, and I suppose also to other 'non American' members. Quite honestly: "Do you
really need all this to start a successful hobby?"
Let me, as an 'amateur' ichthyologist just run through a 'non chemical, non additive
setup' that served myself and many other millions in the hobby successfully for several
decades long before all these chemicals and additives became popular.
Preparation was the key, and for us 'oldies' it was a container/s in the back yard that
collected clean strained rainwater. This was our source of top ups, our new water supply,
and often our source of live food, if the mossie larva or daphnia got into it. We would
set the tank up, fit the u/g filter, and then arrange the pre-washed gravel. Next we would
fill the tank with our pre-aged water from our rain tub, bring it up to the right
temperature, let it stand a few days, normally three to ensure the heat was constant and
there were no probs. In those three days we would arrange plants and rocks, then perhaps
introduce a guppy or two. The old pH testing strips from the chemist gave us a quick idea
of the pH level, and if it was alkaline we would run a bit of peat in the filter bowl for
a day or so to bring the level right. If it was too soft and acid we would add a bit of
limestone or coral chips to the box filter and keep an eye on the pH until it was where we
wanted it. Basically that was it, with little or no stress to the fish. Our calculation
for fish content was to allow 4 square inches of surface area per inch of fish, but with
an air supply this could be increased. Water was never added unless it was exactly the
same temperature as the water in the tank, and newcomers were never added until they were
quarantined for ten days. Plants were meticulously examined for nasties and rinsed in a
mild sterilizing solution before adding to the tank. All mainly common sense.
Each tank had it own net and tools, and nothing was ever taken from one to the other.
Dipping of fingers or hands from one tank to the other was an absolute sin, and never
done. Hands were washed before working on the next tank, and any drips or condensation
were wiped away in case it/they dropped from one tank to the next lower one. A single drop
of water can transmit a disease from one tank to another so quickly you wouldn't believe.
Water changes, (in my case) were done on a visual basis. If the water has evaporated
½" from its original marked level I would do a 30% water change, never every few
days, and never more than perhaps once a month, and always using my aged water in the
outside tub/s. Invariably the tanks might have needed a clean up, so in this situation we
would siphon the rubbish off the bottom and into a bucket. The water that we siphoned out
was dumped and replaced by our aged water. This was then our "water change" and
few troubles were encountered. A balanced tank will keep itself free from excess toxins,
e.g., the right water conditions, substrate-plants-filtration and fish, any of which can
cause an unbalance.
Water: Too hard, too soft, too alkaline, too acid, all of which can be
balanced without chemicals.
. Gravel: Too fine causes bad circulation (packs down
tight), especially with u/g filters, whereas too large a gravel will allow food to reach
inaccessible places with dire consequences. Food remains uneaten and quickly fouls the
tank. Remedy: go for what's right, not what looks pretty.
Slow deterioration of Rocks and Ornaments: Badly selected rocks and
substrates (lime-based gravels, sandstones, corals, shells, ornaments) all of which will
change your tank conditions as they slowly leach or dissolve over time. That ornament or
substrate may look great, but is it killing your fish?
Plants: Too few plants, no hiding places for fragile fish causing fish
to be bullied. Again, find out the likes and dislikes of your plants: for instance, most
Crypts prefer dimly lit areas, etc. Shallow gravel will not produce good plants. Bank your
gravel to the rear of the tank (at least 3") and plant accordingly, big deep rooted
plants to the rear, small types to the front. As with your garden, they need feeding and
something to get their roots into. The wastes from your fish may in most cases be enough
food, but a good root structure and light are essentials for all plants. A 'Plantab' for
aquarium plants slipped under the roots will assist flagging plants.
Filtration: NEVER turn your filter or air off for any length of time,
especially an undergravel filter. The bacteria buildup will skyrocket causing major probs
instantly. Always have some form of air supply running if your tank is in the least bit
crowded. Contrary to belief, the bubbles from an airstone don't put oxygen in the water.
What the bubbles do is break up and disperse the CO2 that can build up in a tank. Watch
for fish lurking near the surface with open mouths, a sure sign of lack of oxygen in the
water. (Not the Gouramis, Bettas etc., who/which are surface breathers) For these fish
ensure the surface is scum free by dragging a sheet of paper over the surface of the water
occasionally. This will completely remove the thin film that sometimes forms on the
surface of the water. Check each day.
Heat Distribution: Fit your heater as low as possible in your tank and
clear of the gravel, and if it is a separate unit from the thermostat place it at the
opposite end of the tank. This will prevent cold spots in your tank and provide a constant
temperature at all levels. (Heat rises, so if possible fix your heater in a horizontal
rather than vertical position for better heat distribution).
Feeding: Feed half as much as you think your fish need, and if it's
not consumed in less than five minutes, you are feeding too much. An established tank will
sustain your fish for a week or more without food, so don't think you need to feed them
every time you pass the tank. "Ooh look, they're all excited at seeing me, they must
" In goes another feed, the third today. How often have you done or
When to feed: Never feed at night then turn the lights off and
leave the fish in darkness - a major problem. The Corys and Kuhlis won't mind, but your
tank will suffer if the night dwellers don't eat all the remains of the food. Small fish
have small mouths, so vary your food type to suit them all. Give them a live food treat
now and again, brine shrimp, micro worms, grindal worms, white worms, or even a chopped up
earth worm if you have big fish. In time you will know their likes and dislikes.
Probs with algae: Throw the scraper away and get a couple of small
Plecos. They're fun, hardy, and adore algae. Snails
To me they are a damn nuisance,
and have no place in a tropical fish tank, but the fish love them if you crunch them up.
Lastly Fish: Impulse buying of fish is fine if you know the fish, and
of course is great for the LFS (Local Fish Shop), but can cause many upsets and even tears
if you don't read first, so take an hour or so and read all you can before you jump in the
Read, read, read - the three rules of keeping fish. Learn every possible thing you can
about where your fish comes from, its water conditions, its temperature limitations, the
food it eats, the species it can live with, its breeding habits, is it a loner or does it
school with others?, and in general, its likes and dislikes. Piranhas and Neons have an
adipose fin, and are distant relatives, but they definitely don't live together, so read
and learn all you can BEFORE you add that particular fish to your collection. (No comments
on the Piranhas please).
It seems a lot to take in all at once, but all this info is just waiting to be read if
you care to read and study it. My philosophy is that "If anyone can teach me
something I will listen, should it be a child, or a ninety year old." So I am
learning each time I read an article about tropical fish.
We all lose fish at some time or other, and the reasons can be mystifying, but
personally I feel that many of the losses are caused by either sheer neglect and not
making one's self familiar with the fish BEFORE purchase, along with the possibility that
many of the fish were actually poisoned due to the intake of chemicals, incorrect or too
many water changes and such.
We can take a pill for a headache or an ailment, but if we take too many of them it
will undoubtedly kill us. This will possibly cause a lot of backfire from the clued up
aquarists, but I still feel that if you read up on your fish and get to know its habits
and living and water conditions and the neighbours it lives with, then you are well on the
way to having a less stressful and very enjoyable hobby. Many newcomers try it once and
leave quickly after their first failures. We don't want this to happen to you, so read
everything you can about the hobby, consider your situation and your setup, then, and only
then think (very carefully) about your next purchase.
Just a note for people who keep goldfish in a heated aquarium: All
fish have the right to a decent life, even goldfish. I myself have culled thousands of
fish in my time I suppose, but these were either runts or a defective strain that I would
not allow to continue living and breeding for fear they would fill our tanks with some of
the oddities I see today. Selective breed by all means, but don't allow your runts and
defective breeds to enter the world of the aquarist. (Are there any 'true' strains still
out there?) Goldfish are cold water fish, and keeping them at 70+ degrees F will shorten
their life span by many years. We had goldfish that lived happily for ten years, outside
in a pool that would freeze over in winter with over an inch of ice, but come spring they
were always there. The heated tank may also cause undue stress to the fish, who knows. Why
not be a good aquarist and introduce some youngster to the hobby by donating your fish to
them rather than make the fish suffer all it's life? But make sure they read a good book
about goldfish first.