Corydora catfish are a family of fish that are small, perky and playful. They come in different sizes and striking colours and look absolutely fascinating. They can be kept in peaceful community aquariums with other fish species as long as you provide suitable tank mates for cory catfish. But it is not only their appearance making them popular. The fact that they are relatively easy to keep and breed makes them even more attractive to new hobbyists who want to keep tropical fish.
|Size||0.74 – 4 inches|
|Minimum tank size||10 gallons|
|Tank setup||Freshwater with a fine substrate|
|Compatibility||Peaceful community aquariums|
Cory Catfish Facts and Overview
There are many different Corydora catfish species. However, the only ones that are commonly sold as aquarium fish have been bred for generations and have lost their barbels. This is why they do no longer have the whiskers that were discussed in older literature. They can be identified by their slender bodies, paired fins and a very small adipose fin.
Corydora catfish are relatively cheap and can be purchased from local pet shops for anything between £2 to £5 per fish. Fish that are kept as pets or used as feeder fish (which many Corydora catfish end up as) may appear dull and faded due to the stresses of transportation and their unfavourable living conditions.
There are 170 described species of catfish that are currently being recognised as belonging to the family of Cory catfish.
What’s their Origin?
The most commonly kept species are Corydora paleatus, Corydora julii and Corydora habrosus. They all originate from South America and therefore prefer soft, acidic water with a low carbonate hardness.
The appearance of Corydora catfish
Corydora catfish can reach a size of up to 4 centimetres. Frequently, they are much smaller though and only grow up to 2½ – 3 centimetres. They have a lifespan of roughly 8 years if kept under ideal conditions.
Appearance wise, Corydora catfish are most commonly brownish-grey with lighter coloured fins. Several species display beautiful iridescent shades on their body or have dark bands that create a striped pattern on them. Colour variations can be seen in wild populations, but these are rarely kept as pets. Differences between sexes exist among cory catfish. Females are usually rounder, they have wider tails and dorsal fins. In general, the females are much larger than the males. A minimum of 3 females and 1 male, or 5-6 females should be kept per group since this would reduce aggression towards each other.
Corydora catfish are peaceful and very social. They make a great addition to community aquariums as long as they have suitable tank mates that can handle the fact that cory catfish may nip fins from time to time.
They will spend most of their time foraging for food, meaning that you need to provide them with plenty of hiding spots so that they can retreat if they feel threatened. Cory catfish are playful and will appreciate having some floating plants and other decorations in the aquarium to swim around and hide in.
Some species of Corydora catfish are known to be venomous and should be handled with care. They have a venom gland in the back of their pectoral fin that they can use to defend themselves if threatened. The venom is not dangerous for humans but it will cause severe pain and itchiness.
Types of Cory catfish
There are 170 species of Corydora catfish, but only a few of them are commonly kept as pets. The following list names the most commonly kept species in aquariums.
Albino Cory Catfish
Albino cory catfish are available in 3 different species:
- Corydora paleatus
- Corydora arcuatus
- Corydora julii
All these albino cory catfish lack any sort of pigment, which makes them appear rather pale when they are kept under less than ideal conditions. The lack of pigment can cause blindness in some albino cory catfish. In addition, they may be more sensitive to light and may hide from their surroundings on a regular basis.
Panda Cory Catfish
Panda Corydora are not albino. Instead, they have black spots on their heads and backs which look like panda markings. The rest of the body is usually brownish-grey, silver or yellowish in colour. Panda Corydora are believed to be slightly less hardy than other species of cory catfish, but they are still suitable for most community aquariums.
Green Cory Catfish
Green cory catfish are yellowish with greenish fins. As their name implies, they are a light yellow-green in appearance. Shy and reclusive, they prefer spending most of their time hiding.
Pygmy Cory Catfish
Pygmy Corydora resemble guppies and have been labelled as dwarf Corydora since they only grow up to 2 centimetres. They are also more peaceful than other types of cory catfish and prefer schooling with small fish such as neons, guppies or cardinals.
Julii Cory Catfish
Julii cory catfish are closely related to green cory catfish, but they have a black triangular mark on their body instead of green. They originate from the Essequibo River in South America and prefer acidic water with a pH level below 7.0 and a carbonate hardness below 2 degrees.
Emerald Cory Catfish
Emerald cory catfish are also quite small, but they can be easily distinguished by their slender bodies and the dark emerald green colour of their scales. Like other pygmy Corydora, they prefer living in schools with other small fish.
Sterbai Cory Catfish
Sterbai cory catfish originate from different rivers in Brazil and have been selectively bred to develop a variety of colours. Males have larger dorsal fins that give them a bristled appearance. Feisty and territorial, they should be kept with peaceful species in a small school in a densely planted aquarium with plenty of hiding spots.
Habitat & Care
Caring for Corydora catfish is not difficult once you know what to look for. The following guide will help you understand the needs of Corydora catfish and if you are prepared to provide them with suitable conditions, they can be quite rewarding aquarium companions.
The optimum water conditions for keeping cory catfish are:
- Water temperature: 75-82°F or 24-28°C
- pH level range: 6.5 – 7.5
- Carbonate hardness (dKH): 3 – 8 degrees
Nitrate levels should be less than 20 ppm since this may cause them stress.
Tank setup (ph balance etc) is very important with corys. I’d say the most common mistake people make is keeping them in too small of a tank. These fish can grow to 3 inches and they will be much happier and healthier if they have plenty of swimming space.
Cory catfish prefer living in small groups and they won’t thrive if kept as a single fish.
Corydora catfish will do well in tanks that are at least 15 gallons (57 liters) in size. If you have a school of them, they would appreciate being kept in larger tanks with plenty of hiding spots so that they feel secure at all times.
A thickly planted aquarium is ideal for cory catfish to thrive since their natural habitat consists mainly of grassy plants, reeds and fallen leaves. To maintain a clean and healthy environment, a good filtration system is a must. Corydora catfish are susceptible to infections from ammonia and nitrite, so water changes shouldn’t be skipped at any cost.
Place the aquarium away from direct sunlight since high temperatures aren’t well tolerated by cory catfish.
Can cory catfish live with other fish?
Corydora catfish are compatible with most species of community fish since they are peaceful, but it’s important to know their specific requirements before purchasing them.
Suitable tank mates for corys include:
- Tetras (Neons, Glowlights or Cardinal tetras) – They should be kept in shoals of at least 6 fish and ideally more.
- Danios (Zebra danio, Leopard danio) – they can be kept in groups of 5 or more and prefer the shoals to number at least 4 fish.
- Mollies (Short-finned molly, Sailfin molly)
- Guppies (Platies and Mollies)
- Rainbowfish (Harlequin rasbora, Celestial pearl danio)
- Glass fish (Pimephales promelas, Ember barb)
Cory catfish can be quite feisty and territorial. It’s best to keep only one cory in an aquarium since it may become stressed if kept with other corys, especially if they are of the same size.
What do a Corydora catfish eat? (diet)
Corydora catfish are omnivorous scavengers that will feed on floating flakes and granules as well as small insects like worms, larvae and brine shrimp.
To keep their barbels in good shape, it’s best to supplement their diet with frozen or live food on a regular basis.
How many Corydora catfish can I keep in my aquarium? (minimum tank population)
Corydora catfish are schooling fish that thrive when kept with other corys. They enjoy staying close to each other and keeping a school of at least 3 fish will ensure that they are happy. A bigger shoal can be kept in an aquarium as long as there are plenty of hiding spots.
It’s best to keep them in groups of 5 or more since this is the minimum number required to maintain their peaceful social structure. Plus, having more corys maintain the cleanliness of the aquarium.
How often do cory catfish lay eggs?
Cory catfish tend to breed in small groups and they will release their eggs into the water.
A female cory can produce up to 60 eggs per day and spawning lasts for 2-3 weeks.
After the eggs are fertilized, they become adhesive and attach themselves to surfaces like rocks and driftwood. A second round of spawning may follow, but the eggs are more likely to be consumed by other fish.
When they hatch, cory catfish larvae are difficult to raise since they need live food like newly hatched brine shrimps or infusoria.
When Are Corydora Old Enough to Mate?
Corydora catfish can live up to 5 years, but it’s best to wait for them to reach 2-3 years before attempting to breed them.
Breeding cory catfish may prove difficult since they are sensitive during the first few months of their life and it’s hard to distinguish the males from females at such a young age.
How often can you breed cory catfish?
Corydora catfish are prolific breeders that can spawn once every 2-3 weeks. The effect of this can be observed by their rapid decrease in numbers.
To control their population, you’ll have to remove them from your aquarium. You can either give or sell them away since they are sensitive during the first few months of their life.
Mating follows a rather simple process and can be done as long as the tank conditions are optimal for them. Corydora catfish eat live food that has been enriched with vitamins and minerals, such as daphnia or bloodworms, to boost their fertility.
Are they suitable for your aquarium?
Corydora catfish are excellent community fish whose peaceful behaviour makes them suitable to keep with most types of fish.
Tetras, mollies and other small or medium-sized shoaling fish can be kept in the same aquarium to create a lively community where the corys will thrive.
It’s important that they are provided with sufficient hiding spaces since they are a very shy species that may become stressed if the aquarium is overcrowded.
Corydora catfish are one of the most popular aquarium fish since they are easy to keep and bred in captivity.
Plus, they are known to reward their owners with interesting behaviour and for being more than willing to breed.
Corydora catfish are considered useful additions to the community aquarium since they help maintain its cleanliness by eating leftover food that falls on the substrate of the tank.
However, corys can be sensitive during their first few months of life. Until they are old enough to breed, it’s important that you provide optimal water conditions for their survival. Adding snails or shrimps to your aquarium is an excellent way to keep the tank clean and free of decaying plant matter.
How many cory catfish should be kept together?
Corydora catfish should never be kept alone since they are social fish that need the company of their own kind. Keeping them in groups of at least 3 corys will ensure that they thrive and live a long healthy life.
How big does a cory catfish get?
Most Corydora catfish grow no longer than 10 cm, but they can reach up to 15-18 cm when fully grown. The largest cory catfish ever recorded was around 25 cm long.
What size tank do cory catfish need?
Corydora catfish can adapt to a wide range of tank sizes. However, it’s important that the aquarium has enough space for all the inhabitants and has been decorated in such a way that they have sufficient hiding spots.