Corydoras robineae by
Eric Bodrock
“The
Flagtail Cory”, I would say is the most strikingly marked Corydoras of
all. Their tail is the first thing that catches the eye, five or six
bold black horizontal stripes on a white background. Three distinct
stripes in the middle of the tail appear to run into the body pattern,
breaking up into large spots by mid-body. Their main body, which is a
silver/white color, is patterned in what looks like broken stripes along
the back and lower sides. The dorsal fin shows a couple of faint black
stripes, while all the other fins show just a hint of black in them.
I have been working
with this species for about four or five years. I have two separate
groups set up for breeding. The group in a fifteen-gallon tank, on
system “B”, is the group that spawned for me. (If your not familiar
with my breeding Systems, see my article, Cory Crumbs, at my web site at
http://www.alloddballaquatics.com for a more detailed description) This
breeding group consists of thirteen adult fish, ten males and three
females. The sexes are pretty easy to distinguish in adults. Females
grow a bit larger, up to three and a half inches, while the males stay
closer to three inches in size. The females also show a thicker, more
bulky body, typical as in many other Corys. I have seen the females, in
the past, fill with eggs and appear very robust, but without ever
spawning. I didn’t notice this at the time of the spawn and I had no
indications at all that spawning was about to occur. Two days before
their spawn, in the same system, after a large water change, a group of
C. davidsandsi laid eggs. The night before their spawn, C. axelrodi, C.
simulatus and C. oiapoquensis spawned. Water conditions at the time of
the spawn was as follows:
TEMPERATURE = 78
degrees Fahrenheit
HARDNESS (GH) = 160 ppm
TDS READING = 249 ppm
pH = 7.0 – 7.2
A water change, of
approximately forty percent, of straight cold tap water was done two
days before the spawn. A storm front was also moving into the area with
thunderstorms predicted to last for several days. Outside (Pittsburgh
Pennsylvania) temperatures ranged from eighty degrees daytime to fifty
degrees at night. This spawn occurred on May 18, 2001. I had fed the
breeders more live black worms than normal for a couple of weeks prior
to them spawning, this could have helped induce spawning.
The robineae laid their eggs
during mid to late afternoon. About half of the two hundred eggs were
placed on the bare glass bottom of the tank, in the open, along the left
side and closer to the back wall. I would guess that about sixty eggs
were scattered among the roots of a Java Fern and an Anubias plant. The remaining forty or
so were deposited in a couple of small, tight groups on the tank sides,
just about three inches off the bottom. The eggs on the floor were also
laid close together in smaller groups and somewhat in a row. Eggs
measure at two millimeter and are sort of white in color. I thought at
first that none of the eggs were good and they had begun to fungus
already! As to not have “all my eggs in one basket” I decided to
move the plants that were full of eggs into a bare two-gallon tank with an air stone
at moderate airflow. With my fingers I rolled off about
fifteen eggs and placed them into another tank that was already set up
for hatching some other Cory species. I shut off the return water from
the central system in the original spawning tank and lowered the water
level to about five inches.
The eggs began to hatch late on the
third day, spotting a single wiggler on a tank bottom. The remaining
eggs hatched on the afternoon of the forth day. Most of the eggs in the
original spawning tank had fungused by the forth day and only six fry
hatched. The
eggs that were attached to the plants that had been moved produced seven
fry and the eggs I moved with my fingers resulted in
nothing. Within about two days after hatching, I began added a small
amount of Microworms every couple of days to both fry tanks. In the two
gallon I did a cup or two water change every other day & left the
other, larger, tank alone. Within a week I began adding small amounts of
newly hatched baby brine shrimp into their diet and shortly after that,
tiny amounts of assorted crushed flakes were given. The fry in the
two-gallon tank grew slightly faster than the others, I’m sure due to
the water changes. The fry in the small tank were moved into a half
filled, ten-gallon tank on day eighteen. (With smaller fry I like to
keep the water level low to reduce the water pressure on them.) At
twenty-two days their total length reached three quarters of an inch and
at thirty-five days a solid one inch. This is rapid growth for a Cory,
probably because of the small number of them getting some specialized
attention from me! My hopes are to raise these fry and set them up in a
breeding colony, I’m thinking that tank-raised, F1 fish, will be
easier to spawn than wild caught fish.
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