18 Different Tropical Aquarium Corydoras - Rare & CommonCorydoras are the perfect addition to any freshwater community aquarium. They are a small bottom-dwelling fish that is excellent at the scavenging of leftover food, thus ensuring an overall cleaner and healthier aquarium.
There are over 180 species of Corydoras, with many more that are yet to be classified. There are also many variants of this species, which are debated whether they are different fish species or just geological variations. Corydoras range from 2.5cm to 12cm, with many growing between 4 and 8cm in length.
While different rarer species of Corydoras can be found for sale, it is usually a more common species available in the trade. However, beware of any that display very intense colours as these fish may have been a victim of artificial dying by injection or other methods.
Corydoras are endemic to South America, most of which originate from the Amazon basin. The waters of natural habitat are clear, slow-moving waterways, where there is an abundance of vegetation creeping in from the stream and river banks.
Although you can find them in Stoney areas, they prefer softer substrate and are generally located in sandy or muddy areas, where there is an abundance of mulm and leaf litter.
Corydoras will rummage amongst the detritus to locate aquatic organisms for food while using the protection of the riverbanks other growth for cover from predators.
These habitat types are often gathering areas for more significant rivers. They are changed seasonally by rain, which usually causes a drop in the water temperature and is a trigger for spawning. Therefore, you can keep many but not all Corydoras in cooler water, so make sure you check before you keep them in unheated tanks.
Corydoras are peaceful and adaptable fish; they never quarrel and will not cause stress to other inhabitants of the aquarium. Corydoras seem to have two tendencies in the aquarium: either resting on the substrate or searching for food.
It is essential to keep Corydoras in groups; they stick together, mainly when resting; however, they will usually mainly group other Corydoras of the same species. You can see unusual behaviour when the fish race to the surface to gulp air and swim back to the substrate. This is perfectly normal as Corydoras can absorb oxygen from atmospheric air, which is a natural part of their respiration.
Corydoras are adaptable concerning water temperature and fluctuating conditions, and they are susceptible to chemicals, toxins, and pollutants. In particular, nitrates should be strictly monitored in aquariums with Corydoras since they do not cope well with high levels, resulting in the barbells' infection.
It is sensible to occasionally use some carbon or other chemical filtration media since airborne pollutants can cause health difficulties. Some potent treatments can also cause problems, so always be cautious about which chemicals you use in the aquarium.
Lots of regular water changes with conditioned water will ensure good long-term conditions. Most Corydoras prefer slightly soft, acidic water in terms of pH and hardness, although you can keep many common species in harder water quite happily.
Corydoras are easy to house with other fish, especially with other peaceful fish and will thrive in community aquariums. Corydoras have armour plating and spines for self-preservation, which means you can keep them with fish several times their size without the risk of them becoming a meal. However, heavy territorial or aggressive fish should be avoided.
Corydoras do not disturb other fish, so small and delicate species such as freshwater shrimp will make ideal tank mates. Although Corydoras are not big fish, they enjoy some swimming space. As they frequently want to rest every so often, it is advised to avoid other overactive and boisterous bottom dwellers stressing or disturbing the Corydoras.
Mimicking the fish's environment is very important for the fish's overall health and will promote more natural behaviour.
The aquarium should have distinct areas of hiding spots, open spaces and vegetation. You can make hiding spots from bogwood pieces or any decor that creates a subdued and enclosed place where the Corydoras can relax without being harassed by other fish.
Vegetation is essential, and the best types are bushy plants with lots of stems at the base as Corydoras will enjoy rummaging amongst these to find scraps of uneaten food.
They will also use open areas for scavenging activities. The most crucial thing here is the substrate. This should be fine, rounded or smooth gravel or sand; otherwise, the fish's sensitive barbells and mouthparts will get damaged. Larger gravel is too course to dig into.
Wild Corydoras diet includes other bottom-dwelling aquatic organisms and worms, which they located by scavenging through the substrate. You can mimic this by feeding the Corys with a range of frozen or live food.
Even though other tank mates will get most of these foods as they sink, the Corydoras will quickly find the bits that get missed shortly after. However, living off meagre scraps is not sufficient, so ensure you supplement their diet with sinking pellet or wafers. These are often labelled as catfish food which ensures they receive the correct micronutrients necessary for optimum health and vitality.
Corydoras will readily accept flake food but note if a significant amount of food can reach the bottom of the aquarium, it generally a good sign you are overfeeding.
Some Corydoras species will breed much more readily than others, and in many cases, they can be reproduced in the aquarium. Ensuring you can replicate the water conditions each species is naturally found in, so make sure you further research this.
Corydoras spanning can be encouraged by changing the water conditions mimicking the rainy season will trigger this. It is advisable to use remineralized RO (reverse osmosis), rain or distilled water and perform some large water changes while reducing water temperature by a few degrees. Using bogwood that releases tannins will also help.
Corydoras species have different breeding habits, so it is best to research the particular type you plan to breed. Be prepared to separate eggs or fry to a separate grow out aquarium away from all other fish.
Frquently asked questions about the Corydoras
How many Corydoras should I have, and can different ones stay together?
What do Corydoras eat?
What substrate should I have for Corydoras?
What tank size do Corydoras need?
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