Corydoras

Panzerwels
Corydoras catfish © Mirko Rosenaui Fotolia.com

Corydoras (with a scientific name – depending on the family Corydas, Aspidoras or Brochis) are a real enrichment for the aquarium and enjoy great popularity among aquarists.

The peaceful and sociable group animals are always eye-catchers and extremely useful.

In the wild they are found in Central and South America, where they can be found with over 150 species.

The diversity of species is described in detail below.

Armored catfish family

The Corydoras belong to the family Callichthyidae, which is divided into two da subfamilies. Only one of these subfamilies is actually used in aquaristics. This is the Corydoradinae, to which the following genera belong:

  • Aspidoras
  • Brochis
  • Corydoras
  • Scleromystax
[/su_list
]The other subfamily is the Callichthyinae, which is known as callus catfish. This family is rather rare in the aquarium. It has the genera:
  • Callichthys
  • Dianema
  • Hoplosternum
  • Lepthoplosternum
  • Megalechis
[/su_list
]Most species of Corydoras are very peaceful and sociable. Also in the care the panel catfish is relatively easy to handle. Especially as a beginner you should concentrate on certain species, with which the breeding is not difficult. They live as group animals or schooling fish.

Differentiation of the genera

So that one can distinguish at all, to which family the armored catfish belong, the number and the appearance of the dorsal fin rays are usually examined:

  • Aspidoras 6-8 Dorsal fin blasting
  • Corydas 6-8 dorsal fin rays (but significantly larger than Aspidoras)
  • Brochis 10-17 dorsal fin rays (largest species of catfish)

Description of the cory

Life expectancy:up to 10 years
Size:from 2 cm - 95% under 8 cm - large species up to 20 cm
Water:especially clean for breeding
pH value:6 - 8
Water hardness:2 - 25° dGH
Temperature:22 – 26° C
Behavior:mostly peaceful
Origin:Central America, South America
Posture:Society, Group
Nutrition:
Aquarium size:medium
Facility:Hide and seek
Ground:sandy
Swimming zone:Floor
Family:Callichthyidae

Natural habitat

In Central and South America, the armored catfish can be found in the distribution area from Trinidad to Argentina. Everywhere where there is no strong current, one finds it, because the Corydoras catfish likes standing and slowly flowing water. It prefers especially the muddy and sandy underground. This should be taken into account when setting up the aquarium. The populated waters have a very low oxygen content, which is further reduced by organic decomposition products. Therefore, tank catfish have developed an additional intestinal respiration during their evolution. Fish that are able to get oxygen with their intestines are called intestinal breathers.

If you have these great ornamental fish in your aquarium, you will quickly notice that the Corydoras catfish regularly shoot to the water surface at an incredible speed for the bulky body and help themselves to oxygen through the intestinal mucosa. Due to the wide distribution of the catfish species, it is not possible to limit the exact water temperature, but you have to look at the temperature of each species in detail. For most species you are right with 22 to 26° C. For a short period of time (a few days to weeks) the Corydoras catfish can also withstand other temperatures. Here the temperature can rise up to 30° C. The same happens in the low temperature range up to 18° C. Some species from the south, like from Paraguay and Uruguay, even withstand up to 14° C. Both in terms of pH-value and water hardness the Corydoras are very robust and very tolerant in a wide range. You can find more about this in the profile.

Appearance

Corydoras have received their unusual name because of their bone-like armoured skin. The bone plates lie on top of each other like roof tiles. A typical feature of their appearance is their compact, stocky body, which has a rounded head shape. The dorsal line falls away to the caudal fin and the belly is flat. Like other catfish species, the Corydoras catfish has two barbels on the mouth, more precisely on the upper lip. In most Corydoras catfish the shape of the dorsal fin is triangular. The front fin ray helps the catfish to put up its dorsal fin.

Corydoras have a very large adipose fin compared to characins. This is maintained by a ray, which is spiky. Due to Weber's device the catfish can hear extremely well under water. Small bones transmit sounds from the scarf on the labyrinth of ears to the swim bladder. Thereby the audible is amplified.

Corydoras catfish size

In contrast to the callus-catfish, which is to be classified as a loner and grows up to 30 cm, most armored catfish remain rather small with a maximum body height of 8 cm. They grow very fast to sexual maturity, which they reach at the age of about 5 months. After that the growth slows down, but continues until death. 95 percent of all Corydoras catfish remain under a body height of 8 cm.

Especially small species of Corydoras are very popular. Aspidoras and Corydas are among them. Brochis become comparatively large.

Corydoras attitude

Corydoras are relatively quiet contemporaries. Nevertheless they need enough space to swim actively. The minimum aquarium size is ten times the length and five times the width. For most species of Corydoras, the height of the tank does not play a major role (exceptions: Dwarf Corydoras pygmaeus, Sickle-spotted Corydoras (Cordoras hastatus) - these species swim freely in the tank). This approximate rule of thumb counts per fish. You should never keep a Corydoras catfish alone, but always in a group of at least 5 to 10 animals.

All non-aggressive ornamental fish are suitable for socialization. Especially with those that live in the middle and upper aquarium zone. We also have many Corydoras in our aquarium and depending on the tank you can observe that too much stocking and too lively fish can slow down the harmonious Corydoras. In tanks, which are not so lively, the Corydoras show a clearly more active behavior and come to the fore much more often. It is also possible to let different species of Corydoras live together in a group. Usually they join together. Especially well suited for socialization are:

  • Dwarf cichlids
  • Characins
  • Angelfish
  • Tooth Carps
[/su_list
]But also other fishes can be socialized with the Corydoras catfish without problems
.

Ground

As ground one takes sand or fine gravel with tank catfish, this must be formed absolutely round. Corydoras rooting through the sand and would injure themselves on sharp edges.

Facility

You should make sure that there are free lanes on the ground so that they have enough space to swim. But they also like to hide. So one should have caves, roots and the like ready. They like to stay there during the day. In the evening hours they are much more active.

Planting

Plants are very much appreciated by the armored catfish. Especially large-leaved plants with overhanging leaves offer them resting places. As a solitary plant you can plant the spear leaf or even java fern, which you can put on stones. If you plant nixica, you can observe how the fish dig out the plants so that they continue to grow while swimming freely. Also hornwort can be put into the sand in order to offer the catfish some hiding places. Especially in the breeding tank the herb is a good hiding place for the young catfish.

Water quality and care

When caring for Corydoras catfish, the chemical composition of the water is rather unimportant. Important is a high water quality, which is shown by the low bacteria density. Especially Corydoras from black water biotopes need especially low-germ aquarium water. With the right aquarium filter system on biological basis this is no problem. Further maintenance steps that help here are:

  • Addition of plant products (humic substances from peat and dead leaves)
  • a lush planting of antibiotic plants
  • regular partial water changes
[/su_list
]The partial water change should be carried out every one to two weeks, up to a third of the water can be changed. If the pool is not very crowded, you can only change a fifth of the water. Make sure that the fresh water has the same temperature.

The addition of leaves (alternatively as liquid preparations) is not only important for the water quality, but also serves the healthy nutrition of the Corydoras catfish. The following plant components are suitable for this:

[/su_list
]You can simply add these during the water change.

With aquarists you can find mostly the following Corydoras:

[/su_list
]This is not only because these catfish are very beautiful, but also because they are very easy to care for. They can also cope with much worse water quality, because they live in water bodies that are mostly organically and bacterially very heavily polluted. Therefore they show an enormous robustness against germs.

When caring for them it is important to know the exact species of Corydoras catfish. Therefore you should note down the name exactly when you go to buy Corydoras catfish. This is the only way to meet the exact needs of the fish afterwards.

Life expectancy

In nature they do not reach a high age with only one year. In a well maintained aquarium the life expectancy can be several years. Large species even live up to ten years.

Nutrition

In nature, the armored catfish feed mostly on decayed plant and animal residues. As a dietary supplement you can - as described above - feed leaves and other plant parts. As main food you can feed ordinary dry food, but also live food and frozen food is gladly taken. Corydoras are known to eat leftovers, which means they eat what other fish leave over. Therefore it is very important that the other fish leave something behind.

But this does not mean that they are only lurking for leftovers. Live food, especially Tubifex and mosquito larvae, is very popular. They pull the food from the sandy bottom. If you have particularly fine gravel, you will also be able to observe how the Corydoras catfish sometimes get up to half of their body stuck in the sand. This is no cause for concern. Also food tablets and granulates are gladly accepted.

Breeding Corydoras

Marmorierter Panzerwels
© Lucia Bence / Young Corydoras

The breeding of most species of Corydoras is no problem. But especially in the breeding tank you should pay attention to a very good water quality. About 40 species are especially suitable for breeding. If you are a beginner and want to start breeding Corydoras, you should concentrate on the Marbled Corydoras or the Metal Corydoras. Here the breeding has the best chances of success.

Especially problematic is the breeding of wild catfish and imports, which often do not produce offspring in captivity in the aquarium.

For successful breeding, the first thing you need is the right number of groups with catfish ready for mating. You can try it with five males and three females or three males and one female. In order for the females to be ready to spawn, a food with a lot of protein is necessary. Especially mosquito larvae are suitable for this. The water should be partially changed daily. The temperature also plays a role, this should be lowered by 5° C, and then returned to its original level. The water hardness is set to 5-10° dGH, the pH-value to 7, and the temperature is between 26-30° C.

By this method the Corydoras can be spawned all year round. Whoever tries it with wild catches should consider the season of the country of origin. With the beginning of the rainy season the mating season usually takes place.

The Mating

Now the time has come: by swimming around excitedly, the little wine shows the male that it is ready to spawn. One male will now block the female's path and press his head crosswise into the flank of the female. Thereby he releases a cloud of sperm. The female now forms a pocket with the pectoral fins where she places some eggs. After that the common work is already over. Corydoras are substrate spawners. That means the female cleans a surface smooth and then sticks her eggs on it.

Now comes the tricky part - Corydoras are spawn predators and eat their own spawn, so you have to put the eggs in a safe place. You put them into the rearing tank. With a little skill and experience you can also offer the female a smooth little sloping disc when spawning. If the female accepts it, you can simply take it out of the tank and put it in the rearing tank.

In the rearing tank there is extreme hygiene with as few germs as possible. A slightly disinfecting agent that inhibits the germs helps to prevent the eggs from becoming fungus. Please do not add too much of the agent. In only one week the first young catfish are hatched. After that they feed on their yolk sac for two days, then they need a food supplement. You can see that by the fact that they swim freely afterwards. Now you can feed Artemia, Cyclops, infusorians and nauplii. On the sandy ground no food remains or mulm may remain. If in doubt, clean it. If you pay attention to the partial water changes and the cleanliness, there will be no bigger losses.

Corydoras species

As I said, there are many species. If you add to this the fact that new ones are added regularly, we would be happy if you help us to keep the list up to date.

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