I bred Corydoras as first priority for 10 years, but changing job and other things put a stop to it for some time. I parted with a lot of species wich are for the most part maintained and bred on by other Danish Corydoras enthusiasts. My remaining stock have been keeping the livebearers and shrimp company but haven't spawned due to the parameters of my tapwater.
The chosen species to have a go at were Corydoras boesemani and Corydoras gryphus, more commonly know as C7.
Corydoras boesemani has not been commonly found in the hobby until Ingo Seidel and Hans Georg Evers brough some back from Surinam a few years ago. Since then they have become more common between dedicated Corydoras hobbyists. They have proven not too difficult to breed and are actually doing fine left alone with eggs and fry remaining in the adults tank.
It is a very nice sand-coloured species with black markings. Some males can even have a slightly extended dorsal.
Corydoras boesemani male.
Peek-a-boo...Corydoras boesemani is in my experience a shy species.
I use frozen bloodworms, newly hatched Artemia and various sticks, granules and pellets for conditioning my fish. Especially Earthworm-sticks are popular. Waterchanges are done regularly (I try to do a 50-60% change every week) with temperate rainwater. Maybe slightly cooler than the tank (23C. approx.) but not really cold like needed for some species. Eggs are relatively large and placed all over the tank.
Fertile eggs from C. boesemani.
Breeding tank. Notice the eggs on both left and right side of the front glass.
My Corydoras breeding tanks are often furnished with a thin layer of sand and some leaves (Beech, Oak) and some bogwood. Sometimes Javafern are attatched to the wood. Mostly I have a clump of moss in there as well.
The other species, Corydoras gryphus, was not scientifically described until recently and known under the codes C7 and CW24 for many years.. The species come from Southern Brazil and Argentina. My fish originates from Hans Georg Evers and are (as I remember) of Argentinan origin. A small fish from the paleatus-complex with males showing high dorsals and sometimes having small squabbles. Very entertaining with noone harmed.
Males can have different colouration with actual albinos showing in broods from time to time.
Normal coloured male...
Very pale coloured male...
Very dark male...
Waterchanges are done with quite cold rainwater (12-14C) and again 50-60% waterchanges. Eggs are placed everywhere, but a most are put on the glass behind mops or plants.
Typical egg-placement for C. gryphus.
For this species, I remove the eggs and hatch them in a container with an airstone. I never use Methylene blue or Alder cones. Just a couple of ramshorn snails for keeping the eggs and the container rid of bactieria film etc.
For first food I use Bananaworms and newly hatched Artemia. I never use decapsulated Artemia eggs or powdered foods for the fry. It is messy completely destroy the water and kill the fry if you're not looking after them constantly and I can't do that. Only when moved to a real tank I use pellets, powders etc.
Fry with belly full of Artemia. Approximately 1 week old.
When I start feeding the fry I transfer them from the hatching container to one of the breederboxes with waterchange via an airlift. After a couple of weeks in there, the fry are moved to real tank.
Newly hatched C. gryphus. Scale is centimeters.
2-3 weeks old.
At 8-10 weeks they resemble small copies of the adults.