Breeding Corydoras & Brochis.
Posted 21 August 2005 - 01:13 PM
By Alan Hosking James
Aquarists often tend to treat all corydoras (we will include Brochis here as they are similar) as tropical fish, when in fact the genus and even some species can be found throughout the tropics of South America and well into the Temperate regions. The various species inhabit all types of water bodies from deep, warm, Equatorial lowland lagoons to shallow, fast running, cool mountain streams.
With this in mind it can be seen that no one set of conditions is ideal for all cories. So much so that I only keep those species that are suited to the conditions in my fish room. For instance I cannot keep C babatus alive in Summer. Although the fish room can be opened up and has roof vents the water gets too hot even in the lowest tanks with vigorous airation. A lot of us are under the impression that it is always raining in the tropics but even the Amazon region experiences a dry or drier season when streams stop flowing and water bodies diminish. This increases the biomass, reducing food availability and water quality. The rise in temperature and concentration of fish results in low oxygen availability or Dissolved Oxygen Ratio (DOR). Cories have the ability to utalise atmospheric oxygen by gulping air at the water surface. Although this helps them survive the foul conditions in which they are forced to live it also exposes them to predators.
What has this Geography/Biology garbage got to do with breeding fish you ask? Well no fish is going to breed if the food supply is inadequate, water supply foul, temperature too high, oxygen is scarce and it is fighting for survival. As hobbyists we want our fish to reproduce and to do it on the weekend or some other time when we have time to observe and do what we have to do. I like to set my fish up to spawn the evening before I have a couple of days off work. They will not always cooperate but there is a fair chance they will. From our Geography/Biology we can deduce the triggers that induce spawning. The primary trigger is the onset of the wet or rainy season. This event, usually annual , floods and flushes the streams, fills the ponds and inundates the fringing vegetation. Improved water quality, increased DOR , an abundance of food for both adults and fry, and usually a drop in water temperature all combine to initiate breeding urges.
In the wild cories are schooling fish and in the aquarium they are never happy singly or even in pairs but groups of 5 or more settle down well move about and feed continuously.
Tip 1. Keep groups or small schools of cories to condition and settle the fish for breeding. As the aquarist is the source of food for captive fish and not the evvironment
Tip 2. Plenty of suitable high protein food to get the potential breeders into condition; even to the extent of almost overfeeding. We can’t or shouldn’t intentionally flood our tanks, even though I have forgotten the tap on more than one occasion, but new water seems to be another trigger.
Tip 3. An almost total water change with suitably aged or conditioned water. Fast running, shallow water or water surface agitated by wind and rain is high in dissolved gasses.
Tip 4. Increase the DOR of the spawning tank. As all or most of the CO2/O2 exchange occurs at the surface a vigorous air stone, power head or filter spray bar can be employed. A lot of the cories inhabit fast running streams and spawn on a solid surface of some sort.
Tip 5. Create a current or water movement in the tank by placing the air stone in one corner or directing the power head outlet or spray bar along one side. The final trigger appears to be a drop in temperature. As the spawning temperature for various groups of cories differs this has to be predetermined from the species’ geographic origin.
Tip 6. Fatten and condition the potential breeders for a couple of weeks at a temperature 2 degrees higher than that at which you are going to try to spawn them.
Finally the fish have to be sexually mature. Most cories 6 to 9 months old should be starting to feel their oats if fed and conditioned properly. I recently obtained 20 albino C. paleatus from a supplier about midday on Monday. The fish were 4 – 5cm long and in fairly good condition. They were acclimatized to their new home over 24 hours by adding a couple of litres of water from the tank to the drum they were in every couple of hours or whenever I thought of it. They were chucked into their new home on Tuesday and on Thursday evening they started spawning. 50 or so eggs were removed to a hatching jar (500gr coffee bottle) on Friday and by Monday I had increased my original purchase by 200%. It aint always that easy though! How I do it. As my fish room is a 6m x 9m tin shed (insulated) with over 100 tanks I don’t use heaters in every aquarium. I have a space heater for winter to maintain a minimum temperature of 20 degrees C in the lowest tanks.
Cories are spawned according to room temperature at different times of the year in roughly 3 groups – cool, warm and hot. 20 or 30 potential breeders are housed in a bare tank 1200 x 600 x 450 high with a "slow" biological filter. The fish are fattened for 2 weeks on worms, flake, pellets, brine shrimp and ‘home brew’. The tank gets pretty gunked up with the heavy feeding. Then get stuck into the tank with a sponge, cleaning the sides and bottom and stir it all up. Drain out almost all of the water leaving just a cm or two for the fish to flap around in, then fill again with new prepared water. I then place a length of 90mm PVC pipe angled at 45 degrees along one side, with an air stone in the bottom end and turn the air up to "boiling". This raises the DOR and creates a current through the pipe and the increased evaporation drops the temperature a couple of degrees. Spawning activity usually starts within hours with the "easy" fish and the pipe is replaced after 24 hours. Spawning may last 3 or 4 days, but the major drop is in the first batch. Not all the eggs are placed in or on the pipe. A couple of hundred will end up stuck on the glass sides where ever there is a bit of water movement but these are easily removed with a razor blade and hatched in jars with 3 or 4 drops of methylene blue. After hatching all the fry are raised in bare nursery tanks for 6 weeks or so until they are robust enough to go into grow-out ponds.
I am not advocating that this is the only way to breed cories but just the procedure I now employ after more than 40 years of playing around with these chunky little catties. I don’t guarantee 100% success rate but failures are very rare.
Hope these tips are some help to someone.
- Clownz!! likes this
Posted 07 July 2006 - 09:04 PM
If you are still on this website - it is a 3.5 year old post I am extremely envious of you.
I these days only have 2 tanks and as such breed the corys in 1 tank which is a community tank.
In days gone by i had 11 tanks going and was breeding different Corys left, right and centre mostly in winter months but in Summer months species like Rabuti an Zygatus loved the warmer temps.
As for Cory Barbatus I have been breeding them since 1993 and although summer months are a serious struggle in which they pant like crazy and clearly are not at their best. By freezing ice cream containers with purified water - purifier on normal sink tap water is all i have and adding to the tanks will keep temps below 30 degrees in tank with the aid of air cond and they have survived. I currently have 4 generations of Barbatus and they are breeding as we speak in a community tank that contains 4 species of tetras, Neon Blue Rainbows (praecox) and 26 species of Corys and 3 L104's Lorys. The Barbatus originate from a batch vebas got in early 2000 ish -They breed with a species thats not mentioned in any of the catfish books I have - I have 10 books in total that feature Catfish 7-8 specially and am not aware of any other publications on them and also they breed with 13 year old Adolfi of which the original pair are from the first batch Vebas ever got in back in 1993.
The biggest problem Cory Barbatus have is being susceptable to Hole in the Head something I have contended with on the batch from 1995 and 1997 and 2000 and 2004 from Vebas - seems the only place that still brings them in???
People I speak to with exception to owner of Morley Aquariums seem to deny that Barbatus can get Hole in the head but I have lost over 15 adults to it and over 400 young not to mention in trying to treat it the only ever recorded breeding group of Cory Blochi Vittatus which arrived here in Perth back in 1993 labelled as 'wild caught' batch from a German shipment Vebas had back in when they were in original premises out of the house in Justinian St Palmyra.
- Clownz!! likes this
Posted 22 April 2013 - 08:54 PM
Posted 20 October 2013 - 12:20 PM
Posted 21 October 2013 - 05:51 PM
My brothers corys spawn about a week after he remembers to turn on the heater and clean the tank ... He dosent feed them anything special just these bland unbranded pellets from aquarium city , he has only two of them in a 75litre w/ a rainbow shark and neons, ones an albino the others not... there almost as bad as my convicts!!
Posted 22 March 2014 - 08:27 PM
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