Panda Corydoras - Reproduction

Reproduction

Corydoras panda follows, with a few minor deviations, the standard model for breeding for the genus. Stimulus for breeding consists of the influx of cooler, oxygenated waters into their habitat, usually corresponding in the wild with the onset of the rainy season. However, while some Corydoras species require a temperature drop in the aquarium for spawning to be stimulated, in the case of Corydoras panda, the temperature drop appears to matter much less, as specimens have spawned in the aquarium without a temperature drop. The addition of new, clean, oxygenated water appears to be the primary stimulus for this species. In the wild, the appearance of new water courtesy of the rains is followed by an increase in the populations of assorted food organisms, and feeding upon these conditions the fishes for breeding.

Once conditioned fish are stimulated into spawning, males begin chasing females energetically. Females begin developing eggs within their reproductive tracts, and when 'ripe' (laden with eggs), become receptive to the attentions of the males. Eventually, one male will succeed in courting a female, using his barbels to provide stimulation to the female, usually beginning with caresses of the female's caudal peduncle, followed by caresses of the fontanel and the front of the head. if the female is receptive, then the male positions himself before the female, so that the female's mouth is in close proximity with one of the male's pectoral fins. The male then clasps the female's barbels between the pectoral fin and the body, and this stimulates the female to press against the male's side. When seen from above, the fishes form a 'T' shape when conjoined thus, hence the term 'T position' has become conventional in aquarium circles when describing the breeding of Corydoras catfishes.

Once the male and female are in the 'T position', the pressing of the female against the male's body stimulates his release of sperm. Though the exact mechanism of fertilisation has yet to be scientifically documented, from the observations of aquarists who have been successful in breeding Corydoras catfishes, it seems likely that the female takes the male's sperm through her mouthparts, and directs them through the gills, in a current that carries the sperm to her pelvic fins. At this point, the female releases a single egg (occasionally two), and purses her pelvic fins in order to provide a receptacle for the freshly extruded egg, which is then fertilised.

One difference observed between the adoption of the 'T position' in Corydoras panda, when compared to other Corydoras species, is that the exercise is frequently more acrobatic in appearance, with the 'T position' being adopted in mid-water, some distance above the substrate, rather than resting upon the substrate as is the case with the majority of other Corydoras.

Once the female is carrying a fertilised egg within her pelvic fins, she then seeks an egg deposition site. The choice of such a site is frequently, though not always, a mass of fine leaved aquatic vegetation. In the aquarium, the plant known as Java moss, Vesicularia dubayana, is of considerable utility as an egg repository for Corydoras catfishes, even though the plant is not a South American native, and panda catfish females will choose large clumps of this plant readily as safe deposition sites for fertilised eggs. The female is frequently pursued by one or more males as she seeks the deposition site, each male presumably seeking to be the chosen mate to fertilise the next egg. Up to 25 eggs may be produced by a single female during a single spawning, which may take place over four to five hours.