Corydoras are fascinating fish that scour your tank for bits and scraps of food. Because they tend to stay at the bottom, you get to fill the middle and upper portions with other fish like tetras, mollies, or even goldfish! While around 3-5 species can be seen in some pet shops, there are actually over a hundred species of corydoras, most of them extremely hardy, inexpensive, and easy to keep. With that in mind, this article focuses on some of the more popular species of corydoras: the pygmy, bronze, panda, and peppered cory, comparing and contrasting their looks, behaviors, and required care.
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Pygmy Cory: The Under-Cat of the Catfish Family
Pygmy corydoras are often overlooked because of their rather dull colorations and tiny sizes (growing to a maximum of around 1.2”!), but they make up for it in personality; pygmy corydoras are some of the most active species of corydoras, sniffing around not just the bottom, but the middle and upper parts of the tank! From afar, you might mistake them for a school of tetra, since they are able to zip around the tank as a shoal, exploring every nook and cranny, scouring every bits and scraps of food they can find. They do best in larger groups, but fortunately, they don’t require as much space as the rest of the catfish in this article. You can, in fact, keep ten of them in a 10 gallon tank due to their diminutive size. You might even see larger tanks keep more than 50 of them! If you’re looking for a tiny scavenger with a big personality, look no further than the pygmy cory.
Panda Cory: The Bottom-Dwelling Bullet
While pygmies love swimming in the middle section more than the top and the bottom parts of the tank, panda corydoras, maintaining the same level of energy as the pygmies, zips and ricochets around the bottom of the tank. They’re a bit bigger than pygmies, growing to an average size of 2”. The markings on their bodies – the black stripe that goes over their eyes, the black accents near the tail and on the dorsal fin, are reminiscent of the markings of the panda, which, as you can guess, is why they’re named panda corydoras. Their behaviors are similar to that of coolie loaches – they tend to swim quickly from corner to corner, shooting up to the surface and back down. If you need a tiny fish that stays at the bottom, the panda cory is a perfect choice, especially for community aquariums housing smaller fish like tetras and dwarf cichlids.
Bronze Cory: The Cookie-Cutter Bottom Dweller
Bronze corydoras are probably the most common species of corydoras, being sold in pretty much 99% of all pet shops. Featuring a dark black body that quickly tapers to white at the bottom, bronze corydoras flash an iridescent bronze color that sometimes appears green under certain lighting conditions. The albino cory comes from the same species, but comes with a milky, pinkish body with a flash of luminescent silver, and a pair of deep crimson eyes. The bronze corydoras you see in pet shops are most likely raised on fish farms because of how easy they are to care for, raise, and breed. For the beginner, the bronze cory is a perfect choice for a bottom dweller. They tend to do better in groups of at least six, so a tank with at least a 20 gallon long footprint is recommended. If you need a scavenger that has a track record of hardiness and peacefulness, the bronze cory fits the bill.
Peppered Cory: The Cool Cat
The peppered cory is the more relaxed catfish in the family. Some aquarists, in fact, would go so far as to call them sluggish and lazy, hovering or perching along the bottom of the tank, then charging for bits of food they spot. Because of this, they don’t get as much love as the other more active corydoras. The splotches of black scattered across its body make it look more like a crossover between a Dalmatian dog and a bronze cory. The dorsal fin is a lot shorter than that of the bronze cory, therefore making it look like it has a small sail on its back. While this might seem like a minor detail for some, this actually adds a nice aesthetic touch to a school of peppered cory sailing and cruising along the bottom of the tank. Like the bronze cory, the peppered cory also comes with an albino variation, but this variation is quite rare and may command a much higher price. Pepper corydoras are just as hardy as bronze corydoras, and will mix well with placid fish like angelfish. If you need a smooth sailor scavenging along the bottom of your tank, the peppered cory is your cat.
In summary, for smaller tanks of around 10 gallons, pygmies do great as middle-dwelling fish, while pandas do better as bottom-dwelling fish. Pandas have more distinct and familiar patterns that a lot of aquarists love due to its uncanny resemblance to that of a panda bear, while pygmies have a more “peppered” pattern. For larger tanks of around 20 gallons, bronze corydoras and peppered corydoras are great choices, with bronze corydoras being the best choices for those who want a bit more movement and liveliness, and peppered corydoras being the best fit for those who want a calmer, more relaxed fish.
With over a hundred species and counting, corydoras never cease to surprise the fishkeeping community with new splashes of color, unique shoaling behavior, and excellent scavenging skills. With breeders continually searching for new strains and varieties, new ones are bound to pop up at least every decade. We talked about the four classic corydoras: the pygmy, panda, bronze, and the peppered cory. While new strains and species come up every so often, these four classics have consistently won the hearts of many aquarists, both beginner and advanced. Before venturing off to find unique and expensive new species of fish to add to your tank, you might want to consider these four classics.