Corydoras eques

Corydoras eques is a beautiful and fascinating little fish to keep but is a bit more difficult to breed (of course this can pose a nice challenge).

Corydoras eques

Corydoras eques was first described in 1877 by the Austrian zoologist Franz Steindachner. At the time it was described as Osteogaster eques. They are part of the Callichthydae family or family of the Armored Catfishes. They got this name because they lack scales and instead have two rows of bone plates on their sides which makes their armour. It is a relatively large family with over 300 species but only part of them have officially been described.

The name Corydoras can be split up into two parts. Cory means helmet and doras means skin, a wrongfully used reference to its armour. The species name derives from Latin and means Knight, Horseman or Rider, hence its common name.


The color of Corydoras eques partially depends on the substrate they live on. Their flanks can be fairly dark to a somewhat lighter turquoise/blue. Just behind the eye across their gill plate, they have an orange vertical band. You can find this orange also on top of their back and at the edges of their caudal fin. Sometimes they show a dark band that starts at the top of their head and runs to the back to the base of their caudal fin. Their belly is whitish.

With a total length of around 6 centimeters, it is an average Corydoras compared to other Corydoras species. The males stay a bit shorter and can reach a total length of around 5 centimeters. Their body is relatively short and so is their snout. You can see the difference between males and females when they reach adulthood. The females grow a bit larger and plumper. Males are built a bit slimmer.

Just like other Corydoras species the Corydoras eques is a peaceful fish. They can be a bit more active than other Corydoras species. You will probably see them swim endlessly from one side of the aquarium to the other, especially when you keep a school of decent size or keep them in a special species aquarium. As soon as you get closer to the aquarium they will come to the front and swim up and down to the glass. It is a schooling fish that feels more comfortable with at least 6 of them together, they will even feel better in a larger school.

You can keep them in a community aquarium together with other smaller or middle-sized fish like Tetra’s, Danios or Rasboras. Keep in mind that holding them together with larger fish will make them skittish and hide a lot. If you keep them with fish that will try to eat them they have a nasty surprise. They can spread their pectoral fins and lock them in place, this way they will get stuck in the throat of their predator. It is better not to combine them with bigger, hunting species…you will probably lose both.


Their type locality is Rio Solimoes in the Amazon basin near Codajas in Brazil. This town lies halfway between Tefe and Manaus. Not much is known of other locations they could live but from time to time similar-looking fish are being exported from Peru. It is still unclear whether these fish are the same species or not.


Corydoras eques forages on the bottom looking for food particles. They are omnivorous and will eat anything edible. You can feed them with most sinking foods like living and frozen foods like mosquito larvae, daphnia, bloodworms etc. You can also feed flakes, tablets, and granules but keep in mind they have small mouths.

If you keep them in a community tank make sure enough food reaches the bottom. Check on them to see if they get enough down there to feed on. Don’t assume they can live on the litter on the ground because the don’t, Corydoras eques don’t feed on detritus (neither does any other Corydoras species).

The Aquarium

Because Corydoras eques is a schooling fish they will need some bottom clearance so you will need an aquarium of at least 90 centimeters in length. Decorate the aquarium with fine (filter) sand. In photos, you will often see fine gravel but we don’t recommend using gravel. The gravel can damage their barbels or even wear them off. They need these barbells to find the food particles in the substrate. It is better to use sand. I usually use filtersand because these sand grains have the same diameter, this prevents the sand from clumping together which makes the bottom rot.

The rest of the decoration is up to you as long as you provide some cover for the Corydoras eques. You can use driftwood or plants or any other cover you can create.

They will need crisp clean and well-oxygenated water. Make sure to clean your tank very regularly and create some current at the surface. Don’t hesitate to change your water with cooler water, they really love it and you will see them react to the cooler water right away.

Breeding aquarium and conditioning

Breeding Corydoras eques can pose a bigger challenge than other Corydoras species. In order to get better results, you can set up a special breeding tank. Use a smaller aquarium of around 50 centimeters in length. Setup a sponge filter, heating etc. Decorate the aquarium with a thin layer of sand and lots of fine-leaved plants and some floating plants.

Keep the water parameters stable for a couple of weeks. Feed the full-grown fish with a variety of foods but make sure you also give them black mosquito larvae. Make sure the fish are fully grown and use a ratio of 2 males to every female.

The Spawn

You will see the female Corydoras eques grow and get more rounded bellies. This usually means they are getting full of eggs. You can initiate the spawn by changing 50% to 70% percent of the aquarium water with cooler water. Add some more aeration with an airstone and add some extra current with a small streamer. Aim the current at the glass, many Corydoras species tend to place their eggs on the spot where the current hits the glass. Sometimes Corydoras eques differs from other species. Some of them want to lay the eggs between the fine-leaved plants or even in the floating plants near the surface. You will have to find out what works best with your fish.

Raising the fry

The eggs hatch after 3 to 4 days. They will use up their yolk sack in the next couple of days. As soon as its gone you can start feeding them microworms and newly hatched brine shrimp. As they grow you can start feeding them larger foods like crushed flakes etc.

Corydoras eques fry are highly sensitive to fluctuation in your water quality so make sure to keep your tank impeccably clean and make sure you aerate the tank. They have a better chance of surviving if you add a thin layer of sand on the bottom instead of using a bare bottom.

The fry are fast-growing. After 10 days they already have a nice colour pattern. Within 5 to 6 weeks they are small copies of their parents. At the age of around 3 months, they are big enough to be moved to a community tank. This attractive Corydoras is always in demand. Because they are not often offered at stores usually you can sell them at a good price.

Transporting Corydoras

Many Corydoras species have a poisonous defence mechanism to prevent being eaten by larger fish. In case of danger they can spread the spines in their dorsal and pectoral fins and lock them in place. This way the Corydoras gets stuck in the mouth or throat of the predator, a clear signal for other predators to leave them alone. When netting Corydoras you will see them get stuck in your net with their fins. Take care when you are getting them out, if the spine punctures your skin the tip can break off and remain in your skinn. The wounds can be painfull and often can become infected.

Besides the pointy spines, some Corydoras species can release a toxin into the water when they are stressed or in danger. When transported in too small a volume of water or too many Corydoras in the small space, this can lead to rapid death among the fish. It is therefore preferable to only transport the Corydoras with other Corydoras and not too much in one bag. Because little research has been done on this venom, it is not clear whether this venom is spread from the gills or from the spines.


You will not often find Corydoras eques in your local fish shop. If they offer them they will more often be nicely colored Corydoras aeneus so pay attention to what you are buying. Corydoras aeneus is usually much cheaper than Corydoras eques. It is a nicely colored and fascinating fish to keep, but a bit harder to breed (which of course again is a nice challenge).



John de Lange

Copyright images

Hung-You Chen
Gert Jan van Beek


Additional information






First described by

Franz Steindachner


Social behaviour

Breeding behaviour


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