Our Fascination
with Discus
By Tom & Pat Bridges
From the beginning we found ourselves drawn to these large, gentle
creatures with their delicate beauty. A very generous gift from a friend
provided a pair for our first 100 gallon tank. They were beautiful blue discus
and they were fascinating.
Unlike some discus they were not at all shy. They would meet us a
the front corner of their tank when we came downstairs and follow us by swimming
along as we walked past.
We set to work to treat them like the visiting royalty they really
were. Clean polyethylene sheets were used to carefully collect rainwater in an
attempt to bring their tank closer to the soft acid water of their natural
habitat. It was wet, unpleasant work rushing out into the backyard during
rainstorms to collect the water, but nothing was too good for our new friends.
Sadly, we found out too late, that the rainwater, with its load of heavy metals
from a local industry, carried a death sentence.
Even now, so many years later, I have trouble swallowing when I
remember the tragedy our ignorance brought on. We decided to have no more
discus until we knew a lot more about keeping and breeding a wide variety
of tropical fish.
Several years and many thousands of baby fish later, we thought it
might be safe to try again. We proceeded to buy young discus by way of a
commercial wholesaler. I have no quarrel with wholesalers. They do a
difficult job and, generally, serve our hobby well but we had no success
with the discus they provided. Some of them lasted almost a month before
they succumbed to hole-in-the-head or some other less identifiable
disease. Several hundred wasted dollars later, we were about ready to give
up for the second time.
When
some young brown discus were held up for bids at a WNYAS, (Western New
York Aquarium Soc.), auction I almost passed on them. My hand seemed to go
up of its own volition. The auctioneer asked, "How many bags?" I
heard myself say, "All three." We were now the owners of three
medium sized tank-raised discus. As it turned out they weren't in the best
of shape. Once they were unbagged the cloudy eyes became evident. I
thought I knew why the bidding hadn't gone very high.
We put them in a high twenty gallon tank and gave them only routine
maintenance, food and care, expecting nothing. A few months later I
noticed that two of them had relegated the third one to a corner of the
tank. I moved it to another tank and gave them a slate. It wasn't long
before they used it for their first spawning attempt. As I recall, they
didn't get it right the first few time but eventually they produced
several nice batches of babies that fed off their parents' sides and grew
rapidly. They made us proud.
We kept and raised eleven youngsters from the first successful spawn.
They had their own 50 gallon tank and eventually we sold them as proven
mated pairs. (That means they had produced viable eggs.) Five pairs! Over
the years we've had both kinds of luck but the good kind with discus was
just beginning.
Brown
is beautiful but when some young brilliant turquoise discus came up at a
Hamilton auction we were ready for a change. We paid a lot more than last
time, but went home with four beautiful juveniles. This time they were in
perfect condition. They were given a high twenty gallon tank and, it took
about a year before anything significant happened. They caught us by
surprise because they were still fairly small but they knew what to do. We
had two pairs. We housed them in separate twenty gallon tanks next to each
other. After a few false starts one pair achieved success and produced
quite a number of successful spawns. They never seemed to produce as much
body slime as the browns but it was adequate and the fry survived. The
second pair had one or two small successes but tended to eat the eggs
pretty consistently. That's what lead to our experiments with artificial
hatching and rearing but more about that later.
Our successes with discus began in the early 80's so I'm sure you will
understand if I don't try to document all the pairs and the second
generations that blessed our fish room with fry.
I don't want to create the impression that there were no problems. We
never had the huge spawns of 200 plus babies that 'real' discus breeders
talk about. Ours ranged between 35 and 100 with a lot less than that left
after culling. We found that most of our breeders produced well for about
a year or so and then tailed off and eventually quit completely. After
swearing off rainwater and wholesale stock we found health problems fairly
manageable provided we worked our butts off maintaining excellent water
quality. Discus seem to be more susceptible to external and internal
parasites than many other fish and don't respond well to even a little
neglect. They do respond well to frequent, regular water changes. (If
possible, soft acid water above 80 degrees F.) How to produce that became
less of a problem when we acquired a Reverse Osmosis Filter.
When
this RO was attached to our water line it pre-filtered the water through a
5 micron cartridge, then a carbon cartridge and finally a membrane which
theoretically will only allow pure water molecules to pass. The result is
a small but steady supply of very soft water and a larger amount of harder
waste water. (That waste water doesn't need to be wasted. It is excellent
for African cichlids, Anableps and other hard water loving fishes. Your
garden will do very well on what's left over if you can figure a way to
get it out there.)
We have always collected the RO water in a large plastic barrel in
which a submersible heater keeps the temperature about 84 degrees F. An
old canister filter is used to cycle the water through a bag of peat moss
to help produce the desired acidity. This isn't very high-tech, I know,
because I've seen some of the sophisticated setups that dedicated discus
breeders use, but it has served our modest needs and was all we could
afford.
As to the peat moss, we like the crumbly Canadian stuff. We mix it with
RO water and boil it in a big enamelled pot for about 20 minutes. If the
pot is covered securely and stored in a cool place the peat will keep for
awhile. We find that we have to use it to refill the bag in the canister
filter every couple of weeks or it loses its effectiveness. (By the way,
the water in which the peat has been boiled can be used in moderate
amounts to stimulate some tetras to spawn.)
We are
in the habit of adding a small amount of pH buffer to the water before
adding it to the discus tanks aiming at about 6.5 pH. We also add a little
regular tap water to help with the buffering. (Pure RO water has very
little buffering ability and can sometimes plunge to a very low acidity
level.) Bear in mind that all this is helpful in getting adult discus
pairs to breed but not absolutely necessary. It hasn't been necessary for
baby and juvenile discus. Once they were eating brine shrimp nauplii on
their own and had been removed from the parent's tank, we found that they
grew fine in regular water as long as it was frequently changed and their
tanks were kept clean and uncrowded.
We feed our discus a variety of high quality flake, frozen and live
foods. I stress the quality. Frozen brine shrimp is one of their
favourites as long as you can get the good red stuff that doesn't look
like it was dead for awhile before it was frozen. By far the cheapest,
most nutritious frozen food we have used is a homemade recipe that
contains a mixture of fish, beef heart, beef liver, baby clams, eggs,
greens and lots of other good stuff. It is thoroughly processed with
gelatine powder as a binder and frozen in flattened plastic bags. One of
the things we learned is that a discus that doesn't want to eat is either
sick or is going to be sick.
Among
live foods they really like is tubifex worms. They make an excellent food
if you can grow your own and, (we were able to do this for a time), know
that they are safe. Commercially available live tubifex is sometimes
contaminated with parasites which can be very bad news. Most of our discus
enjoyed the live brine shrimp that we grow in plastic ponds in our back
yard but one pair performed weird contortions every time we put some in
their tank. Apparently they were convinced that these creatures were
really baby discus that just didn't know how to behave. I never saw them
eat a single shrimp.
I was never very good at telling the sex of discus. Dumb luck took care
of the problem most of the time but I did pick up a couple of clues over
the years. Female discus are often, but not always, a little smaller than
males of the same age and, when they are ready to spawn, the female's
breeding tube, (ovipositor), is large and stumpy. The male has a more
slender, pointed tube and, of course, it isn't an ovipositor.
The
red turquoise pair shown on the front of this newsletter were perhaps the
most unusual discus we have ever acquired. We spotted a tank of these in
one of the former pet stores in St. Catharines. They had been purchased by
the shop from the wife of a hobbyist who had unfortunately died. The store
owner had divided them into large, medium and small discus. They were in
beautiful condition and we bought one of the larger ones. At home the next
day I scratched my head and finally came up with an idea. (Remember that
females are quite often a little smaller than males.) We went back and
purchased a medium, (ten dollars cheaper). This pair was carefully
quarantined for about 6 weeks. For the last 2 weeks a small, culled discus
from one of our rearing tanks was placed with them to see if it might come
down with something to which they had resistance. Nothing happened so they
were moved to a high twenty gallon tank complete with spawning sites. The
day after the move they spawned. Furthermore they raised that spawn and
every spawn thereafter. Although they didn't lay large numbers of eggs,
they continued to spawn about once a month for the next year and they
remain the only discus we've ever known that never ate their eggs or their
babies. Their 'Best Parents' award was well earned.
Unlike this charming couple, some discus pairs never learn to keep
their eggs and/or babies. If you really must have some of their offspring
sometimes the only answer lies in artificial hatching and rearing. We
tried it a few times early on and found that the hatching part was easy.
Almost the same technique used for angels would get us a nice batch of
free-swimming discus babies all looking for something to eat. In my
opinion no one should even try spawning discus until they have some
success with angels, but I'll briefly review the procedure we use. We
first arrange to have the parents spawn on a removable object, (sometimes
by making almost all other surfaces unavailable). A small, clean tank is
prepared with a mixture of water from the breeders' tank and some fresh RO
at a temperature just slightly warmer than the spawning water. A
submersible heater is installed and adjusted. An airstone is dropped in
and adjusted so that a stream of bubbles will keep the water circulating
gently. A lid is obtained and the bottle of methylene blue drops is placed
nearby. After the parents have finished spawning and fertilizing and
before they start eating, the spawn is removed and placed in the hatching
tank. Methylene blue drops are added to the water until you can barely see
the eggs. (Usually about 10 drops per gallon.)
About
the third day when the good eggs have hatched and there are wrigglers on
the slate we exchange the airstone for a charcoal-loaded box filter
covered with bridal veil to keep the babies from getting sucked in. This
effectively removes the blue from the water and allows us to see what's
happening.
By the seventh day we have removed the slate with, usually, most of the
dead and fungused eggs still stuck to it. Now the discus babies start
swimming around looking for something to eat. If they were angels we would
just put some newly hatched brine shrimp nauplii in the tank and watch
their bellies turn pink. We tried that with discus and half a dozen
actually survived but most of them simply starved to death. They expect to
find their first food stuck to their parents' sides. As yet they don't
seem able to chase and capture their dinners.
We gave up on artificial rearing until after I retired. By then I had
read and heard a great deal about success with egg formulas and feeding in
bowls so I decided to try again. Instead of egg I decided to use a product
sometimes called microfood and to make a paste of it by mixing it with
dissolved gelatine powder.
The
result is something that looks and feels like thickened egg yolk but
doesn't spoil as quickly when stored in the fridge. Pat contributed a
large porcelain mixing bowl.
I
smeared this concoction on the inside of the bowl and also on a piece of
amber coloured plexiglass that I hoped to use as a parent substitute.
I
drilled a hole in it and attached some fish line so it could be suspended
in the bowl and moved up and down to bring more of the food within reach
of the fish. I made up a bucket of half RO and half regular water at the
temperature of the hatching tank and put some of this in the bottom of the
feeding bowl. I then proceeded to syphon the babies from their hatching
tank into the bowl with a small syphon made of a length of rigid plastic
tubing to which a suitable piece of airline had been attached. The water
level in the bowl was adjusted and the plexiglass 'parent' lowered so that
food was within reach of the babies.
I
covered the bowl as much as possible to slow the rate at which the water
would cool off. Since our fish room is pretty warm, this didn't prove to
be much of a problem. While the babies ate for the next 20 minutes or so,
I took the opportunity to change about half the water in the hatching tank
and clean out any fungused eggs or other debris. From time to time I
lowered the 'parent' and raised the water level in the bowl to bring fresh
food within reach of the babies.

To finish the routine I used the remaining prepared water to top up the
hatching/rearing tank, removed most of the water from the bowl and then
used my syphon to transfer the, (not quite so hungry), babies back into
their tank.
Now that doesn't sound so bad, does it. The catch is that I had to do
that routine approximately every four hours for two days. There were some
losses but most seemed to be thriving. On the second day I started
crushing a little newly hatched brine shrimp nauplii into the smeared
mixture as well as letting some live nauplii swim about in the bowl. I was
watching for pink.
The
literature says that if you haven't got them eating shrimp on the third
day, you wipe it out and try again with another hatch. By the middle of
the third day I had approximately 85 babies with pink bellies and I felt
really, really good. From there on it was a piece of cake. I just had to
feed them small amounts of newly hatched shrimp regularly, syphon out what
they didn't eat and change water frequently. I gradually shifted them to
complete regular water. They grew rapidly so I soon moved them to a
fifteen gallon rearing tank and started expanding their diets.

I think you might like to try this or some variation of it once or
twice but my wish for you is that you get a pair of discus that don't
think it's proper to have their kids for lunch.
Written and placed with permission by:
E-mail: Tom & Pat Bridges
Website: Tom
& Pat Bridges Website |