Breeding Corydoras natteri by Mark Bryson

Breeding Corydoras nattereri

by Mark Bryson
First published in the newsletters of the Paisley and District Aquarist Society (Scotland), the Catfish Study Group (U.K.)., and scotcat.com
Aquarticles

Breeding Corydoras nattereri has taken me quite sometime to achieve. During October 1995 while on one of our club outings to The British Aquarist Festival in Manchester we visited BAS Aquatics in Bolton where I purchased my five C. nattereri.

Photo Credit: Helen Burns.

Description: Light grey to gold body with blue-green stripe down side. Length 5-6 cm.

Maintenance: This species prefers water to be colder than is normal for Corydoras and I would recommend 72ºF/22ºC. Initially I housed them in an 18"x12"x12" tank with a sand substrate and Java fern plants.

Filtration: Air driven box filter in one corner and sponge filter in the opposite corner.

Feeding: Tetra Prima, quality flake, tablets and frozen bloodworm. Normally I don’t use live food with the exception of newly hatched brine shrimp for fry. I am currently experimenting with grindal worm cultures.

Breeding:
After quite sometime trying the usual tricks with corys to get them to spawn - i.e. large water changes using cold water which drops the temperature about 6 degrees, nothing was happening. I more or less gave up on them.

In April’97, eighteen months after their arrival, I decided to use the tank they were in for something new and moved the C. nattereri to a 27-gallon tank (39"x15"x12"). Filtration was external canister plus a large double sponge filter. No substrate was used but I included a large piece of Java moss which covered half of the tank. I then left them with no further disturbance from myself.

At the end of April 1998, while doing my usual water change in their tank I moved the Java Moss and noticed a young catfish darting away towards the back of the tank. It had to be a young nattereri as this was a species tank.

My five original nattereri consisted of four males and one large female which was almost twice the size of the males.

I decided to try and get them to spawn again:

Sunday: 25% water change was carried out using water straight from the household water supply, pH 8.3. Prior to this the tank conditions were pH 6.0 and temperature 73ºF/23ºC. After the 7-gallon water change I knew this would make quite a change to the water parameters but I decided to go ahead anyway.
Day 2 Tues.: I removed nine eggs from the Java Moss.
Day 3 Wed: 12 eggs.
Days 4-5 Thurs/Friday: A further 19 eggs removed. This totalled 40 eggs, which were placed in a small show tank with water from the spawning tank, to which I added one drop of Methylene Blue. An airline was placed in the small tank to keep the water circulating. Any infertile eggs were removed.
The fertile eggs were tan coloured and got darker until on the third day they hatched.
A further two days and they were free swimming, approximately 1/8th inch in overall length.

The following weekend I repeated the same procedure again with the water change, and on day three I collected 24 eggs. By now my compliment of nattereri young numbered 43 - ½ inch fry. During these two "controlled" spawnings 64 eggs were collected of which 12 were infertile and 12 fry died, giving me 43 fry. There were also some fry darting about the parents' tank.

It caused me a bit of concern as to why I lost 12 of the fry as they were being fed with micro worm, newly hatched brine shrimp and plenty of water changes using water from the parents' tank. I soon realised that the tank holding the fry was sited 3 feet higher than the parents' tank and was at least 5 degrees hotter. I then moved the fry tanks to a colder part of the fish house and since doing that there have been no further losses.

At the age of six weeks the fry were moved from their 12"x 10"x 8" rearing tank to a 18’’x12’’x12’’ growing-on tank and they will be moved on to a larger tank as they grow.

One month after the first spawning I repeated the whole procedure yet again. Day 3: I spent quite sometime removing 97 eggs from the Java moss. Tank conditions at time of removal: pH6.5, temperature 71ºF/21ºC.

Conclusion: Never give up trying to breed Corydoras Catfish as they will surprise you all the time.

Any comments or thoughts on the above article can be sent to the author at the following e-mail address m.bryson@ntlworld.com