[Ebook] Encyclopedia of Aquarium & Pond Fish – Directory of Freshwater Fish – Catfish – Corydoras

Directory of Freshwater Fish

Catfish

Corydoras

Schwartz’s Corydoras (Corydoras schwartzi)

• ORIGINS: South America, where it is restricted to a tributary of the Rio Purus in eastern Brazil.
• SIZE: 2 1⁄2 in (6 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

Schwartz’s Corydoras is distinguished by dark marks that run through each eye and meet in front of the dorsal fin on the top of the head. There are about 150 different species of corydoras catfish, distributed in the more southerly parts of Central America and also through northern South America. Corydoras are small, attractive catfish. They have proved very popular, being ideal for a mixed community aquarium. Conspicuous and active during the day, corydoras tend to occupy the lower part of the tank. Low rockwork, such as small pieces of slate, will serve as vantage points for these catfish. Schwartz’s Corydoras, like many species, has a limited distribution in the wild but is quite adaptable in the aquarium. Regular water changes are important, however, to keep nitrate levels low

Three-Striped Corydoras (Corydoras trilineatus)

• ORIGINS: South America, occurring in the Rio Ucayali, Rio Ampiyacu, and the Yarina Cocha River in Peru.
• SIZE: 2 in (5 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 68–79°F (0–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

A variable but vibrant body patterning, including a large black mark on the dorsal fin, characterizes these corydoras. Females are generally slightly paler in color than males, with a smaller patch on the dorsal fin. The “three stripes” in the common name of this species refer to the central stripe running along the side of the body and the lighter lines above and below.

Green Corydoras (Corydoras aeneus)

• ORIGINS: South America, widely distributed from Venezuela and Trinidad down to La Plata, Argentina.
• SIZE: 2 3⁄4 in (7 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 68–79°F (20–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.5–7.0).
• TEMPERAMENT: Peaceful and social.

This popular corydoras lacks dark markings on its yellowish-brown body. Instead, there is a strong iridescence on the face and along the upper part of the back. This iridescence ranges from green to copper, depending on the light. Several color variants exist, including an albino. The larger, often more rotund, female actively initiates spawning. The eggs are laid in small batches among aquatic vegetation, and hatching takes about five days. The young initially need fry foods.

Panda Corydoras (Corydoras panda)

• ORIGINS: South America, where it is confined to the Ucayali River system in Peru.
• SIZE: 1 3⁄4 in (4 cm).
• DIET: Live foods, algae, and prepared catfish foods.
• WATER: Temperature 68–77°F (20–25°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

These tiny corydoras are named for their pattern of black markings on a pale background, reminiscent of a panda’s coloration. They will scavenge any uneaten food on the floor of the tank before it starts to decompose and reduce the water quality. Nevertheless, all corydoras should be given their own food. Partial water changes every three weeks will aid the water quality, and an effective filter will help oxygenation.

Black Sail Corydoras (Corydoras melanistius)

• ORIGINS: South America, where it is restricted to the Orinoco River in Venezuela.
• SIZE: 2 1⁄2 in (6 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 68–75°F (20–24°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

A striking silvery background is the backdrop for the irregular rows of spotted markings extending over the body of these corydoras. There is a black band through each eye and a dark area at the front of the dorsal fin. It is not easy to distinguish the sexes, but females can be identified at spawning time as they swell with eggs. Black Sail Corydoras have been bred successfully in aquariums.

Peppered Corydoras (Corydoras paleatus)

• ORIGINS: South America, occurring in southeastern parts of Brazil and the La Plata basin, Argentina.
• SIZE: 2 3⁄4 in (7 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 66–79°F (19–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

The Peppered Corydoras, one of the most widely kept species in the group, has black spots on the flanks that may sometimes fuse together to create a banded appearance. Iridescence may also be evident over this part of the body. This was one of the first tropical fish to be bred in Europe, having been spawned successfully in Paris in 1878, and it will reproduce readily in aquariums. Peppered Corydoras are relatively hardy fish.

Pygmy Catfish (Corydoras pygmaeus)

• ORIGINS: South America, occurring in Brazil in the Rio Madeira and its tributaries.
• SIZE: 1 in (2.5 cm).
• DIET: Live foods, algae, and prepared catfish foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

These tiny corydoras are the smallest members of the group, as their name suggests. Aside from their size, however, they can be distinguished by their pattern of horizontal black stripes, with the central stripe broadening near the dorsal fin. They tend to swim throughout the tank more than most corydoras, which usually prefer the lower reaches. A small shoal of Pygmy Catfish will make ideal companions for other small, nonaggressive fish.

FEEDING BY TOUCH

One of the most distinctive features of corydoras catfish is the presence of six barbels arranged in pairs around their extendible mouthparts. Two pairs are located above the upper jaw, with the longest pair occasionally extending as far back as the gill openings. The third pair of barbels, which are very short and relatively inconspicuous, are on the chin itself. The mouth, situated on the underside of the body, enables these fish to feed by swimming just above the substrate and combing the surface with the barbels for edible items. Corydoras are also very efficient excavators, digging into the substrate with their mouthparts and using the barbels, which are covered in touch-sensitive cells, to direct them toward small worms and other concealed creatures. Sand rather than gravel is sometimes used as a substrate in an aquarium for corydoras, since it allows the fish to dig more easily. The drawback to sand, however, is that it is more likely to become compacted, so it needs to be turned over with a spoon at regular intervals. Since corydoras will rest on the substrate, any buildup of dirt here is likely to damage their barbels. To guard against this, use a gravel cleaner when a partial water change is undertaken.

Rabaut’s Corydoras (Corydoras rabauti)

• ORIGINS: South America, close to the confluence of the Rio Negro and the Amazon, near Tabatinga, Brazil.
• SIZE: 21 ⁄2 in (6 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

Rabaut’s Corydoras is one of the most striking members of the group, thanks to the contrast between its orange background color and its black stripe. It is now usually considered to be synonymous with Myers’ Corydoras, which occurs in tributaries of the upper Amazon. Females may lay their eggs at or even just above the aquarium waterline on the

Harald Schultz’s Corydoras (Corydoras haraldschultzi)

• ORIGINS: South America, occurring in Rio Tocantins and Rio Araguaia in central Brazil.
• SIZE: 3 in (7.5 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 75–82°F (24–28°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

The underparts of this corydoras are pinkish, while the spots along the sides of the body are so close together that they merge in places to form irregular stripes. The name of this corydoras commemorates the late Brazilian fish exporter Harald Schultz, who brought a number of today’s most popular fish, including the Blue Discus, to the attention of aquarists around the world.

Agassiz’s Corydoras (Corydoras agassizii)

• ORIGINS: Western South America, where it is found in the vicinity of Iquitos, Peru.
• SIZE: 3 1⁄2 in (9 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

This attractive corydoras has a patterning of dark spots against a reddish background. Sexing is difficult, although just prior to spawning, females have a more rotund appearance. If you obtain a small group of these catfish, however, the likelihood is that you will have at least one pair among them. Soft-water conditions are most likely to encourage breeding behavior.

Robina’s Corydoras (Corydoras robineae)

• ORIGINS: South America, where it occurs in the upper parts of the Rio Negro system, notably the Rio Aiuana.
• SIZE: 3 in (7.5 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

The striped patterning of this species is most evident toward the rear of the body, where black horizontal stripes extend out across the caudal fin. Robina’s and other corydoras prefer subdued lighting, which also helps to make their patterning more apparent. In some lights, there may be iridescence behind the gills and also down the flanks. Like various members of the group, these fish should be kept in shoals, rather than singly.

COMING UP FOR AIR

Corydoras originate from rivers and streams with a relatively low oxygen content. Their gills cannot extract enough oxygen from the water to sustain them, so these small catfish have also developed a means of breathing air directly. Every now and again they will suddenly swim upward, almost vertically from the bottom, and break the water’s surface. They gulp down a mouthful of air and dart back down again very quickly to the substrate. Back on the bottom, the corydoras supplement their blood-oxygen levels by absorbing oxygen from the gulp of air, which they store in their hind gut.

Adolfo’s Corydoras (Corydoras adolfoi)

• ORIGINS: South America, occurring in Brazil, where it is found in the Rio Negro and the Rio Uapes.
• SIZE: 2 1⁄2 in (6 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

Adolfo’s Corydoras can be distinguished from the similarly patterned Imitator Corydoras (C. imitator) by its shorter snout and the red coloration in front of its dorsal fin. As with other corydoras, a wellplanted breeding tank with a relatively low water level is recommended for spawning purposes. It should house a single female and two males. The eggs, about 30 of which are laid in groups on plant leaves or even on the sides of the aquarium, hatch after four days. The young will congregate on the substrate until they have digested the remains of their yolk sacs and become freeswimming. At this stage, they will need to be reared on fry foods, before taking flake when a week old. If the adults are well fed, they are likely to breed again a couple of weeks later.

Skunk Corydoras (Corydoras arcuatus)

• ORIGINS: South America, where it is found in parts of Ecuador, Peru, and Brazil.
• SIZE: 3 in (7.5 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

This pink-bodied species has a black stripe that curves along its upper body from the mouth to the base of the tail. Some individuals display slight black markings on the sides of the body as well. It is often confused with the Black-Top Corydoras, which has a very similar scientific name: Corydoras acutus. Corydoras can be kept at a slightly lower temperature than most tropical fish.

Masked Corydoras (Corydoras metae)

• ORIGINS: South America, occurring in Colombia’s Rio Meta and its tributaries.
• SIZE: 2 in (5 cm).
• DIET: Prefers fresh and thawed live foods.
• WATER: Temperature 72–79°F (22–26°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

The black “mask” over the eyes of this corydoras explains its common name, although this feature is also seen in some other species. The body is plain, aside from a black area on the dorsal fin that extends down to the caudal peduncle. These catfish seek their food on the tank floor, so offer pellets that sink rapidly. Live foods such as small worms are a useful conditioning food for corydoras

Bearded Corydoras (Scleromystax barbatus)

• ORIGINS: South America, occurring in the vicinity of both Rio de Janeiro and Sao Paulo, Brazil.
• SIZE: 5 in (12.5 cm).
• DIET: Live foods and prepared catfish foods.
• WATER: Temperature 68–77°F (20–25°C); soft to hard (50–150 mg/l) and acidic to neutral (pH 6.0–7.0).
• TEMPERAMENT: Peaceful and social.

This species, one of the largest known corydoras, exists as two distinct variants. Bearded Corydoras from around Sao Paulo are lighter in color and have less yellow on their bodies than those from the vicinity of Rio de Janeiro. These fish stay close to the bottoms of streams and rivers, hiding in aquatic vegetation when danger threatens. Include rocks and plants in their tank to provide hiding places.

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