Hot Cory’s

Hot Cory’s! Yes these are some of the most sort after species of the whole family, but that is not the point of this article. In a previous piece I wrote about three species that prefer, or should I say needed to be maintained at cooler temperatures to be at their best. Well in this article I will look at three species that most certainly are at their best when kept at the higher end of the so-called tropical range.

The first indication I had of Corydoras species tolerating higher temperatures, let alone it being a requirement for good health and a necessity for breeding. It was a friend back in 1985 that at that time had started breeding Corydoras adolfoi Burgess, 1982. He had been keeping them at temperatures in the low eighties Fahrenheit when they first spawned. It was not until 1994 that I first started to breed them myself, although it was not at such a high temperature. I had been keeping a group of six fish at around seventy-eight to eighty degrees Fahrenheit; it was after the influx of cool water following a fifty percent water change, which triggered the spawning activity. The temperature was taken again at the time shortly after spawning activity had ended and was recorded at seventy-six degrees Fahrenheit. It is also possible that Corydoras duplicareus, a species that is almost identical in appearance to Corydoras adolfoi also prefers warmer water, they are at times found inhabiting the same tributaries of the upper Rio Negro.

The next two species Corydoras gossei Nijssen, 1972 and Corydoras seussi Dinkelmeyer, 1996 are also found inhabiting the same areas in the Rio Mamore system Brazil. The first is most definitely a lover of warm water, which if they are to be successfully bred needs to be kept at temperatures around eighty degrees Fahrenheit if not a little warmer. I first realised their needs for a warmer environment a couple of years ago when a tropical fish wholesaler friend of mine imported a large quantity of Corydoras gossei, half of which were put in tanks on the highest section of the fish room along with some large Discus. The following day I received a phone call from my friend to say that the ‘New’ Cory’s were spawning, then after pause he said “but the Discus are eating the egg just as fast as the catfish were laying them”. I went over to his place as quickly as I could to see if I could see and maybe get some pictures of the spawning activity but by the time I got there it was just as though nothing had happened. I decided seeing as I was there I would buy a group and see if they would give a repeat performance. The first thing that struck me when I started to catch the fish was the fact that the water felt warm, very warm. When I checked it was eighty-four degrees Fahrenheit, had been warmed up in readiness for the arrival of the Discus in the shipment. Apparently one of the boxes of Corydoras gossei had been put in the Discus prepared tank by mistake.

It was a year so later, in May 1999 that my fish first spawned; they were housed in their own eight-gallon tank, where the temperature was an average seventy-eight degree’s Fahrenheit. The tank furnishings were; a ten millimetre layer of smooth grained sand, a small air driven box filter a large clump of Java moss and a piece of bog wood with a piece of Java fern attached. Because of the amount of Java moss in the tank affording the Corydoras gossei almost total privacy, the fact that they had spawned did not become evident until a twenty millimetre long youngster started to show its self. I then decided to move the adults to a tank at the warmest part of the fish house. This tank was a little larger, holding twelve gallons of water and had an average temperature of eighty-two degree’s. This tank was filtered using a theehundred litre per hour internal power filter and only had four pieces of Java fern attached to pieces of bogwood for cover, making observing the Corydoras gossei far easier than when they were in the tank filled with Java moss. Two weeks after being moved to their new tank and the day following a regular weekly thirty percent cool water change, spawning activity could be observed. The replacement cool water reduced the tanks temperature by only three degree’s Fahrenheit. The two females deposited eggs on every conceivable surface; some were even placed on the filter’s outlet spout. On this occasion all of the eggs that could be found were removed and placed into a small two-litre hatching container, which contained water from the main tank. This water was treated with three drops of Methylene blue to help protect the eggs from fungal attack. An air stone was also added for water movement and maximum oxygen absorption. The container kept floating at the edge of the main tank to ensure the eggs were maintained at the same temperature. It took four days for the fry to emerge from the eggs and another two to three days for all the fry to become free swimming. The same procedures were applied to hatching and raising the Corydoras adolfoi as were for the Corydoras gossei. The first foods were micro worm
Followed by alternate feeds of brine shrimp or pre-soaked powdered flake.

Corydoras seussi is a species with a very similar colour pattern to that of Corydoras gossei, the main visual difference being that Corydoras seussi has a longer snout, slimmer body shape and the colour of the dorsal and pectoral fin spines are pinkish orange, Corydoras gossei have yellow orange fin spines. Both species are found in the Rio Mamore river system, from an area known as Est. Rondonia in Brazil. It’s the fact that these two species live together in the same habitat, at least during certain times of the year, which gives me the indication that at least during certain times of the year they are living in the same temperatures and water conditions. It may very well be that when the rainy season starts, both species migrate to totally different areas to spawn in their own chosen niches, only to meet up again as the waters recede. This is only conjecture on my part but it will be a good place to start when I set out conditions in an attempt to spawn these fish.