▷ Armored Catfish – Profile | Corydoras in the aquarium | All info

Data sheet mailed catfish

German name:
armored catfish

Scientific name:
Corydoras

Origin:
South America

Size:
depending on the species 2 cm – 8 cm

Aquarium

Length:
Length from 80 cm width and from 35 cm width for larger species
Length from 60 cm width and from 30 cm width for smaller species

Contents:
from 54 liters

water values

Temperature:
22°- 26° C

pH:
6 – 8

GH:
5° – 10° dH

Behave

Area:
lower area, near the ground

Lining:
Frost, dry and live food, feed for ornamental fish

Behave:
Schooling fish, peaceful

Number:
5-10 animals

Difficulty level:
Beginner

Why armored catfish swim to the surface of the water

Corydoras schwartzi Source: Image on Wikimedia Commons License: Public domain Author: Thomas Land

Mailed catfish can absorb oxygen from the atmosphere, more simply from the air, via their intestines.

From time to time they therefore quickly swim to the surface of the water and immediately back down.

If this happens frequently, it should be checked whether the conditions in the aquarium are good.

Possible causes for frequent surface breathing are lack of oxygen and excessive nitrite levels.

Why armored catfish don’t just swim on the bottom

Mailed catfish don’t always just swim on the bottom. Depending on the species, they swim more or less often in the open water, up and down the windows, along plants, etc.

Due to the additional intestinal respiration, they get additional air when they swim in the upper water layers. Discs and plants are searched for something to eat.

Why are my armored catfish hiding?

Source: Image on Wikimedia Commons License: CC Attr. SA 3.0 Author: Soulkeeper

Some armored catfish are shy and will hide if there is movement in front of the aquarium. Possibly this behavior is more pronounced in wild-caught than in captive-bred animals. In nature, mailed catfish mostly live hidden and only go outside to search for food.

Mailed catfish live in swarms in nature. The swarm size depends on the species. Some species only form small swarms, other species form very large swarms. Many eyes see more than one pair of eyes, and the individual member’s attention is focused more on the preservation of the group than on the preservation of their own lives.

If only one animal in the group behaves restlessly or flees, all the others will be infected and panic, because only the fish that caused the restlessness has a direct connection to the source of danger. Everyone else reacts blindly.

Source: Image on Wikimedia Commons License: Public domain Author: Jofre

This is easily recognizable when a shy group is put together with a group that is not shy. When there is movement in front of the aquarium, all the animals hunt together into their retreat, regardless of whether they come from the originally shy or not shy group.

As a single animal or as a single pair, they often behave completely differently than in a herd. They move everywhere without fear and even eye the keeper.

With thickets of plants, artificial shelters and substrate that matches the color of the animals, the jumpiness can be reduced under certain circumstances. You can try to mask off the aquarium sides and the back wall in a dark color, to use a dark floor and to insulate the light. Unfortunately, these measures certainly do not help.

The lighting is very important. What is important is not the brightness, but whether the lamps used allow shadows to form in the aquarium. Fluorescent tubes have no directed light and therefore cast little or no shadow.

Source: Image on Wikimedia Commons License: Public domain Copyright: Quatermass

When using HQI lights, the armored catfish move along under the low-growing plant leaves. Because they feel unobserved, they lose their shyness.

Armored catfish do not have to fear predators from the side as much as predators from above.

If they get the impression that they are living in full light and that the ground with its markings also offers no cover, they don’t even dare to come out of their hiding place.

The animals also have a very distinctive social behavior. They like to lie in close body contact in root cavities and doze.

Species known to be shy:

Species known to be not shy:

Corydoras leucomelas Source: Image on Wikimedia Commons License: CC Attr. SA 3.0 Author: Soulkeeper.

However, the lists should not be taken too strictly. It is uncertain whether the jumpiness is related to the species. Corydoras aeneus are described by some owners as shy and by others as not shy. On the other hand, even fish of the same species acquired from different breeders often show almost identical behavior. So perhaps environmental factors play the biggest role.

Catfish, for example, hear very well. This is why even a resilient floor can cause you to hear the vibrations transmitted into the water and disappear when someone enters the room.

The quickest measure to observe shy armored catfish is to become part of the landscape. If you sit down in front of the aquarium, the anxious inhabitants disappear first, because that’s how they react to movement. If you sit motionless, everyone will soon be back.

The swarm behavior

Mailed catfish form swarms in nature. Offspring in the safe aquarium often do not follow this rule. Most of the time, however, they remain in visual contact, so that it is more or less a swarm with a large individual distance.

They often swim individually, in pairs or at most several together, unite briefly to form the entire group and then disperse again. The more animals are kept, the more likely it is that the entire group will come together. Different species then often form a common group, at least if the animals are drawn in a similar way.

The natural swarm behavior in the aquarium is probably not really recognizable due to the small aquarium sizes and the small number of armored catfish, especially since there are no predators to form a swarm as an additional means of pressure.

2 films on swarming behavior in nature:

Sand for armored catfish Source: Image on Wikimedia Commons License: CC Attr. SA 3.0 Author: Stan Shebs

Sand is particularly suitable as a bottom for armored catfish. They burrow their mouths deep into the sand to look for food. You can often see the sand trickling out of the gills.

If the bottom of the aquarium is almost completely covered by plants, at least a small sandy corner should be set up for armored catfish

Dwarf armored catfish, such as Corydoras habrosus and C. pygmaeus, are generally much more willing to swim than the large armored catfish species. They sometimes only rarely stay on the ground and do not necessarily need a sand corner. These species are often found in free swimming areas foraging or resting on the leaves of plants.

However, there are also experiences with C. habrosus that they are almost exclusively on the ground and rummage in the sand.
A sandy corner is therefore useful for practically all armored catfish species. For example, a plastic box with sand can be placed in a corner of the aquarium. A Tubifex FD cube or other suitable food can be buried in the sand corner so that it is accepted quickly.

How well or rather how badly armored catfish get along with a certain bottom can be recognized quickly by the barbels. With sharp-edged gravel, the barbels quickly become shorter and can disappear completely. Apparently this can also happen with rounded gravel.
However, the barbels can also be affected by bacterial infections and become shorter as a result. Of course, unsuitable soil can at least contribute to or exacerbate bacterial infections.

Set up a sand corner afterwards

For example, a small freezer box can be filled with sand and pressed into the gravel until the edge is just sticking out. The edge can be well hidden with pebbles or pieces of wood. The sand does not mix too much with the gravel.

There are various ways of getting the can of sand into the ground in a set-up aquarium.

version 1

Push some gravel aside when changing the water. Place an empty plastic bowl in the free space. Then carefully fill in the sand using a plastic measuring cup. This creates a cloud of dust, which soon settles again.

Variant 2

Fill a plastic bowl completely with sand and close with a lid. Dig the shell into the gravel and remove the lid.

Moisten the sand properly before sinking it into the bowl so that as little sand as possible is whirled up.

Variant 3

An empty plastic bowl is positioned and fixed at a suitable place in the aquarium. A household funnel is placed on a 9/12 aquarium hose.
The cleaned sand is put into the funnel and slides through the hose into the switch. If the hose is aimed well, there is very little sand fog.

The funnel or hose must remain dry above the water level. Otherwise the sand will stick in the funnel or hose and not slide into the bowl.

Variant 4

Fill sand into a relatively tall container, but not to the brim. Depending on the amount of sand, measuring cups, drinking glasses, etc. are suitable. The vessel is slowly placed in the aquarium at a slight angle so that the inflowing water can whirl up the sand in the glass but cannot wash it out. When the jar is completely submerged, you can literally pour the sand just off the bottom and it gets where it’s supposed to go. It may help to switch off the filter during this time.

Sex differences in armored catfish

Corydoras aeneus Source: Image on Wikimedia Commons License: CC Attr. SA 3.0 Author: WIKIFAN-UL

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