Spawning of Corydoras Paralleleus

Spawning Corydoras parallelus

Article & Photos by Eric Bodrock

I was fortunate enough to obtain a group of eight F2 youngfrom a German breeder by the name of Johannes Graf.Johannes was kind enough to ship them to my friend’s place in Berlin, where I was staying in May of 2008. Judging by their size, I am guessing that they were about 3-4 months old when I received them. I must also say that even at that size, they are an attractive fish that would instantly go on any Cory keepers’ “wish list”.

The young grew out nicely,resulting in a breeding group of five males and three females. Males are a bit more slender and grow to a smaller size around 4cm than the females,which can reach 4.5cm in total length. An easily recognizable difference in the sexes is the extended dorsal fin of the males. Starting at about five months old it can be noticed and in adults, it is a sight not soon forgotten!

They were housed in a ten-gallon aquarium, filtered with a Poret® foam filter driven with good airflow. Natural sand lightly covered the bottom, a couple of broad leafed Anubias plants provided cover from the overhead fluorescent light and a few round river rocks with a flat stone across the top of them made up the décor. A handful of oak leaves were scattered across the bottom. Water temperatures was maintained between 74°-75°F (23°- 24°C) but fluctuated sometimes in the winter, dropping down to as low as 67°F (19.5°C). The pH also had a wide range varying from 6.2 - 7.1. The total dissolved solids (TDS)stayed between 201-261ppm.

Their diet consisted heavily on live blackworms with pretty much an unlimited supply for them to graze on when they desired. In addition, pellet food, live baby brine, frozen bloodworms and Freeze-dried Tubifex worms were also offered. During the summer months, an occasional feeding of live glassworms and daphnia we also given.

Their first spawn occurred when they were approximately fifteen months old. Spawns occur usually during the daylight hours, starting at the break of day and lasting throughout the day.Eggs are deposited one at a time, mostly on the underside of Anubias leavesand on the glass sides but are occasionally placed on the rocks. On average, about 40eggs can be found during a single afternoon of spawning.Eggs are large at almost 2mm and very sticky. That adhesiveness makes them very easy to remove if you want to move them.I have had several spawns to date and tried various methods of hatching the eggs. Removing the parents, placing the eggs in a suspended hatching container in the spawning tank or moving the eggs into a separate small hatching container all resulted in an average hatch rate of about 80%.

A couple of days after they hatch, once their eggs sacs are absorbed, they are ready to take microworms and soon after, live baby brine. Finely crushed flakes or powdered foods can also be given. Initial growth rate is rapid, but within 3 months, it slows considerably. At about the 8 to10 week old range I have experienced some losses where the young seem to thin out and waste away. I been told by several people that have received some young fish from me tell me they have experienced the same. I have treated with several medications but could not say for sure if it did any good in preventing other fish from having the same problem. Other Cory fry and young fish that are housed with them have never shown any signs of a problem. I’m not sure what the issue is, but Iam glad that it is limited to only a few young fish.

No special care is needed to grow them out. I do regular weekly water changes of about 50% with treated tap water. The sex ratio of the young seems to be a little heavy on the male side. Possibly due to either temperature or pH, most of my spawns have occurred at the lower ranges of the above-mentioned parameters.

They are a great looking, rare Cory that I hope will stay in the hobby for years to come.

Breeding hasn’t proved to be difficult, but as with many oddball Corys, finding the fish to start with is the problem! JEB 6/2010