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he "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.

 

Corydoras robineae

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 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.

 

Click on thumbnails for larger image.

	Eggs on Java Fern roots and Anubias.
	Small cluster of eggs on side of tank.
	Female with eggs deposited on tank bottom

 

The eggs began to hatch late on the third day, spotting a single wriggler on a tank bottom. The remaining eggs hatched on the afternoon of the fourth day. Most of the eggs in the original spawning tank had fungused by the fourth 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.

All photo's by Author.

This article and others can be viewed on Eric's site at www.alloddballaquatics.com