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Corydoras
robineae
by
Eric Bodrock
Finformation,
August
2001
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 “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 you're not familiar with my breeding systems, see my article,
Cory Crumbs, at my web site at 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°F ; 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 millimeters 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 Anubias plant full of eggs into a bare
two-gallon tank with an airstone with 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 adding 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 and 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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