first saw this Corydoras adolfoi
look alike in February of this year when a few turned
up in a tank at Wholesale Tropicals (London), but unfortunately
they were all sold. It was not until Wholesale Tropicals
imported several boxes of these fish as C. adolfoi
that 1was able to obtain several specimens. At first
glance you could be mistaken for thinking that the two
fish are the same, but it is when the fish are seen
side by side that the differences between them become
obvious. In C. adolfoi the black band that runs
down the spine from the dorsal fin to the caudal fin,
starts wide and runs down to a point. In this new type,
the black band, apart from being wider at the dorsal
fin, runs roughly parallel with the spine to the caudal
fin. This black band can vary in width from fish to
fish, in my specimens it varies from approximately 4mm
to 6mm, in fact in one female the band is so wide that
it stretches almost to the lateral line of the fish.
The
fish are housed in a 24 x 12 x
15 tank with swimming pool sand for a substrate
and decorated with bogwood and Java moss. The tank
like the majority of the tanks in my fish house
is filtered by an internal box filter containing gravel
and filter wool. One evening in September whilst checking
the tanks prior to feeding I noticed an odd egg stuck
in the far left hand corner of the tank about two thirds
of the way up the glass. As I watched one of the females
swam straight up to the egg and ate it! Instant panic.
Was I too late or had the rest of the eggs been eaten?
fortunately not, on lifting up the clump of Java moss
I found forty eggs spread right across the base of the
plant. Every egg in the Java moss was as close to the
substrate as possible and certainly not more than a
couple of millimetres above the sand. Another difference
between these two fish is the way in which they spawn.
C.adolfoi will normally lay their eggs all over
a tank, in the corners, on the sides and all over plants.
This broad banded type, it seems only lays its eggs
during low runs over the substrate. Apart from the one
egg seen to be eaten by a female no other eggs were
found other than those in the base of the Java moss.
Unfortunately the actual spawning was not witnessed
but on every occasion the eggs have always been laid
in a similar position. Each egg is 2mm in size and on
being removed from the tank were placed into a container
containing filtered rain water and a drop of Myxazin.
The first eggs started to hatch after four days with
the rest hatching on the fifth day. The temperature
of the water, in the hatching container being 75 - 76F.
On hatching the fry are large enough, once the egg sac
is consumed to take newly hatched brine shrimp. The
growth rate of the fry compared to normal adolfoi is
far quicker. After four weeks these fry have reached
between 12 - 16mm each, far larger than C. adolfoi at
the same age. The body marking appears to be the same
as the smaller adolfoi, at four weeks their eye patch
is already well developed and as well as the body being
mottled there are four dark spots spaced between the
dorsal and caudal fins which as in adolfoi I'm sure
will develop into the black band. The fry are currently
fed two to three times a day, either on brine shrimp,
flake or chopped Tubifex and if the current growth continues
it will not be long before these fry are miniature versions
of their parents.
As to where this new fish comes from, I have not been
able to find out too much about this, except that I
am told that they are collected approximately two hundred
miles further up the Rio Negro than C. adoifoi.
I have also been told that if two groups of these fish
(adolfoi and broad banded) are put in a tank
together they will not shoal together but stay apart
in two groups. I cannot confirm this as both my groups
are kept in separate breeding set ups.
Update:- At nearly six weeks old the fry are
still growing fast, the mottling on the body is spreading
and the dark spots are enlarging to begin forming the
black band. This Article first appeared in the Catfish Association
of Great Britain Newsletter in the fourth issue of 1994.
Since this article was produced, the "Broad Banded"
Corydoras is now been named as Corydoras duplicarous.
The
fish are housed in a 24 x 12 x
