THE CHARMING CORYDORAS PANDA
by Dean Baayens
Reprinted from the "Calquarium" / March 2004
Publication of the Calgary Aquarium Society
As a boy growing up in a small town, we had only one pet store and you'd think that would limit selection. However, the owner was quite the entrepreneur and used to import direct from Singapore and other exotic locales. He'd bring in a new shipment once or twice a month and I was always one of the first people there to see what new and unusual fishes had arrived. It wasn't typically the fishes he purchased that I was interested in, but the unusual by-catch (contaminants) that were mixed in with the purchased stock. Often I could get these fish fairly cheaply, which was in tune with my limited budget. In those days I was into keeping as many different species of fish as possible, and cheap meant more fish.
One day the owner brought in a large shipment of many fish varieties I had never seen before. Some neat fish I remember included red-striped rasboras, giant guppies and Nanochromis parilus, which I was told was a species whose females were brighter in color than the males - they were strikingly unusual but, the fish that really caught my eye was a little, 2.5cm catfish that had a black mask and black markings on it's dorsal and caudal fins. They were about as charming a fish as I had ever seen and I simply had to have them. Immediately I went to the owner and asked, "How much?". Fifty bucks apiece! My jaw dropped and my heart sank; not a chance that mom was going to shell out $100 for a pair of catfish. Seeing my despair, the owner said that if the few dozen he had didn't sell he would make me a deal as I was a good customer ( I think more likely because I was a kid). He went on to indicate the fish in question were the very rare Corydoras panda and he had encountered a worrisome amount of financial risk by bringing in such an expensive little fish. The risk was well worth it for within two days all the fancy little pandas were gone.
For fifteen years I never saw another panda Cory, and it wasn't like I was living in the sticks. I lived in Lethbridge for three years and, when I wasn't living in the city, we made fairly regular trips to fish stores in Red Deer, Calgary and Edmonton. All I likely needed to do was ask for them but, during this time, I was really focused on South American dwarf cichlids, especially Apistogrammas. After making a more permanent move to the big city of Calgary, I finally had a chance to frequent Calgary's great fish shops more often. After a couple years of snooping around, I finally came upon the elusive panda catfish and, to my surprise, they were only nine bucks each. What a find! Quite ecstatic about the stellar deal I'd happened upon, I bought five and took them home. It's funny how something that is, at one point, unattainable never truly loses it's luster.
I released the pandas into a densely planted 33-gallon aquarium I'd recently set up. They were mixed in with a number of other fish and appeared instantly at home in their new surroundings. The pandas didn't seem to have any different maintenance requirements than other Corydoras species I've kept, and did well on a diet of flakes, brine shrimp pellets and frozen bloodworms, with an occasional feeding of live brine shrimp and white worms. Along with weekly water changes of about 20%, they flourished and I expected eggs to be deposited in the near future, but this didn't happen nearly as soon as I had hoped. A year later the catfish had doubled in size and appeared fully mature, but still there were no sign of eggs. I decided that maybe another fish (likely my Ruby Barbs) had been eating their eggs, so I moved the pandas to a heavily planted 15-gallon aquarium, where I raised guppy fry. The pandas seemed pretty pleased with the leftovers from the baby brine shrimp feedings and, within a couple months, I had catfish eggs.
My panda Corys now regularly spawn between October and April in aged Calgary tap water that has a pH of 7.8, a hardness of 150 mg/L (as calcium carbonate), and a temperature typically near 76 degrees F. The pandas natural habitat is in the Upper Amazon River in Peru, where I expect the water conditions are fairly variable, thereby creating an adaptable fish fauna that can likely reproduce in a wide range of water conditions. Most often, spawning is induced by a negative change in barometric pressure or by water changes using cool replacement water ( 1/3 change with 65 degree F water). My pandas generally become restless for a couple hours before spawning, which usually commences just before lights out and continues through the night. When I see my catfish doing their spawning preambles, I predict snow if I haven't changed the water recently. More often than not I wake up the next morning to a blanket of snow covering the front lawn and catfish eggs in the aquarium. When a water change triggers spawning, there's usually a coupe days lag time between the water change and the deposition of eggs.
I have three females and two males in my spawning tank and, typically, only one pair of fish spawn at a time, depositing between 18 and 25 sticky, amber colored eggs between the fronds of a large clump of Java Moss. In my experience, pandas don't often stick their eggs to the side of the aquarium, and I would recommend using Java Moss or perhaps a acrylic spawning mop as a spawning substrate. With a good diet, pandas are really no problem to get to spawn. Raising fry, on the other hand, is a little more difficult. I was pretty worried about losing my very first batch of panda eggs, so I made a call to our local aquarium society's Corydoras guru, Birgit, and developed my technique for rearing panda fry based on her advice.
After the eggs have been spotted, often deep within the Java Moss, they can be picked out using your fingers and placed into a container of water from the spawning tank. I use a two-liter clear plastic container that I float in the spawning tank. Catfish eggs and fry are very susceptible to fungus so I do twice daily water changes of 50%, using the tank water for replacement. I also remove any eggs that have fungused until the eggs hatch, usually in three to five days. A number of articles I've read recommend using one drop of methylene blue per gallon to prevent fungus. I have found this to be unnecessary for pandas, but I've also found, from experience, that other Corydoras species ( such as C. adolfoi) may indeed require this treatment as they are even more susceptible to fungus. Aftet the fry have hatched, I remove the shells and any waste products from the bottom of the tank by using a turkey baster for the twice daily water changing. After hatching, I allow the fry to live off the yolk sac for two days. On the third day I introduce a very small amount of baby brine shrimp, about double what I think the fry can eat, after each water change. If the fry are eating the brine shrimp you will notice their bellies turn bright orange. This is the most critical stage and where the greatest losses occur, and if you're not careful you'll lose the whole batch. (Ed Note: Ingesting shells from brine shrimp can be fatal to very young corydoras. If you are not are there are no shells along with the baby brine, it may be better to feed micro worms for a few days before starting with baby brine shrimp.) Most of the time a small number of fry ( maybe 5 %) won't eat, so you must be diligent in removing dead fry as well as uneaten brine shrimp as you can with the turkey baster or fungus will quickly form. As the fry begin to grow, I gradually increase the amount of baby brine shrimp they receive, and continue on with the twice daily water changes for about two weeks. By this time the fry have increased markedly in size to a length of approximately 1 cm, and are ready to be moved to a grow-out tank. For grow out of 20 or so fry I use a moderately planted 3-gallon aquarium and feed the corys twice daily ( microworms in the morning and brine shrimp at night) with water changes of 30% per week. After about a month, they have grown considerably in size and I introduce a more adult diet, including brine shrimp pellets, chopped frozen bloodworms and white worms. After a couple more weeks the pandas are large and adaptable enough to sell at an auction or give to a friend.
Although I may make it sound like Corydoras panda are easy to keep and spawn, they can be quite sensitive to deteriorating water conditions and stress. Most successful fish keepers achieve good routine maintenance. However, problems related to stress are often more difficult to resolve. I've found pandas need a lot of cover to feel comfortable and display their natural behavior. I've tried raising them in relatively bare tanks and have noticed they are exceptionally nervous under these conditions. Accordingly, I've lost a fair number or otherwise healthy looking fish in bare tanks for no reason that I can think of other than stress. They also don't like to be moved around much and seem most comfortable when kept in groups of six or more. For best results, I recommend obtaining a nice group of six to ten individuals and housing them in a well-planted tank, in which they can make a permanent home.
Besides being relatively easy to keep and breed, Corydoras panda have some qualities that really make them a keeper. To me, the most endearing habit of pandas is the way they snuffle through sand substrates, especially when seeking live baby brine shrimp or white worms. They become incredibly excited when live food first arrives, then settle down to slowly sift through the sand with their sensitive barbels. They appear so sublimely content while sifting sand that I often become transfixed, forgetting about all the things needed to be done, and just watch. Corydoras panda are one of the best additions I've made to my aquariums over the years. I liked them the instant I first laid eyes upon them and I appreciate them even more now that I've had a chance to get to know them better. A charming fish, indeed.
Ed Note: Pandas are one of several Corys that are "mop-spawners", including C. metae, C. davidsandsi and C.axelrodi. They will spawn in regular killi-type acrylic mops (don't use wool yarn as it decays). An extremely successful European breeder claims that there should always be a layer of sand on the bottom of Cory tanks - he uses bare tanks with 1/8" of sand over the bottom. Tank bottoms get a layer of "slime" on them and the sand helps alleviate this condition. As I said earlier, feeding microworms for the first few days keeps fry from dying because if ingesting brine shrimp shells, which compact them. After a week or a little less there is no problem. One more suggestion - avoid light when hatching cory eggs. The darker the hatching container the better.