If you’re thinking about getting into fish keeping, then the 10-gallon aquarium is the perfect size to dip your toes into the hobby. Not only is it large enough to allow you to keep a wide variety of fish, but it’s still small enough that any maintenance is quick and easy. But that doesn’t mean […]
Bronze Corydoras – The Care, Feeding and Breeding of Bronze Corydoras (Bronze Cory Cat)
Bronze Corydoras Stats
Minimum Tank Size: 20 Gallons (75 Litres)
Care Level: Easy
Water Conditions: 5.5-7.5 pH and Soft to Medium
Temperature: 72-84 °F (22-29 °C)
Maximum Size: 3 inches (7.5 cm)
The bronze corydoras (Corydoras aeneus), also known as the bronze cory and green corydoras, is a small, tropical catfish that ranks among the most popular catfish kept in home aquariums.. They are native to South America and can found from Argentina in the south, all the way up to Columbia in the north.
They primarily tend to inhabit slow moving rivers and streams, and prefer areas with shallow, muddy water. With that being said, they can also be found in everything from fast flowing rivers, to nearly stagnant pond and marshes.
They are one of only a handful of fish that can thrive in stagnant water, and they do this by utilizing their specialized ability to breath air from the surface of the water. Even in the home aquarium, you will often see them darting to the surface to take a quick gulp of air, and then diving back down to the bottom.
Bronze corydoras stay relatively small in the home aquarium, and the females grow slightly larger than the males. Most females will grow up to 2 3/4 inches (7cm), while the males generally top out at 2 ½ inches (6.5 cm). A well cared for bronze corydoras will easily live for 10 years in a home aquarium, and it’s not unusual for one to live significantly longer.
Housing
It’s commonly accepted that the minimum tank size for bronze corydoras is 10 gallons (37 litres), but they only seem to truly thrive when provided with a 20 gallon (75 litre) “long” tank. The width of the tank is more important than the height, as they spend the majority of their time digging and sifting through the substrate for food.
In the wild they combine into large schools with dozens of fish, so they should always be kept in groups of at least five. Even when they are kept in groups of five, they may still exhibit some shyness, and their schooling behavior only really shines when they are kept in groups of at least eight.
When choosing a filter for bronze corydoras, it’s important to remember that they appreciate calm waters, and steps should be taken to ensure that the current is kept to a minimum. You can still use an HOB (hang-on-back) filter on the tank, but the tank shouldn’t be over- filtered.
I would strongly recommend choosing an Aquaclear Power Filter
You also need to provide a suitable substrate for bronze corydoras and any substrate with sharp edges should be avoided. Bronze corydoras spend much of their time sifting through the substrate foraging for food, and their barbels are easily damaged by any sharp surfaces.
Idealy, the substrate should be composed of sand, though soil will also work if you’re willing to deal with the numerous issues that soil brings along with it. If you decide to go the gravel route, make sure to choose a high quality aquarium gravel – preferably one of the numerous ones coated with epoxy.
Feeding
Bronze corydoras are omnivores, and mainly feed on small crustaceans, worms, and insects in the wild. This diet should be reproduced as closely as possible in the home aquarium, and this can be done through feeding a high quality flake or pellet food, and live or frozen foods.
Their favorite live foods are bloodworms, blackworms and brine shrimp. They tend to ignore other live foods that remain near the surface of the water and should only be fed live foods that sink to the bottom. Their tastes in frozen foods are similar, and they can be fed brine shrimp, blackworms, bloodworms and daphnia.
If they are kept in fish tanks with other fish, effort needs to be taken to ensure that they are receiving enough food. A common issue is that other fish will eat all of the food, before any of it can sink down the to catfish. This can be remedied through the use of pellets, or feeding flakes and sinking foods at the same time. I recommend using Hikari Sinking Wafers, which is one of the best foods on the market.
Breeding
Breeding corydoras catfish is not difficult, and in many instances they will breed on their own in a home aquarium. But if you want to trigger breeding, there are certain steps you can take that will increase your chances.
To begin with, try to ensure that you have more males than females in the tank, and a good ratio to aim for is two males for every female. Once the females in the tank begin to plump up with eggs, it’s time for you to attempt to trigger breeding.
The rainy season in the wild always triggers breeding in bronze corydoars, and you can simulate this in the home aquarium through a single, large water change (50%+ of the water). The water that you use should be slightly cooler than the water in the aquarium. If a single, large water change doesn’t work, you should then try small, daily water changes (around 10% of the water) until the fish begin mating.
You can usually tell that mating has started, when the males begin to chase the females. This will usually go on for several days, until the females then start to chase the males around the tank. Shortly after that occurs, you will likely notice several catfish in their breeding position, which is known as the “T-position”. The females mouth will be adjacent to the males mid-section, while the male generally stays at a 90 degree angle to the female.
After they have copulated in this position, the female will deposit her eggs in a place that she has cleaned before hand. Any tank that has been set up for breeding purposes should contain fine leaved aquatic plants, or a breeding mop to provide a place for the females to lay their eggs. If none are provided, they may still deposit the eggs on a flat surface in the tank or the aquarium glass itself.
After the female has laid her eggs, all of the adult bronze corydoras should be removed from the tank. In most cases, the eggs in the tank will hatch in four to five days, and they will continue to hatch for up to 24 hours in some cases.
The newborn fry should be fed infusoria, and then can be moved on to baby brine shrimp, microworms, and powdered flake food or any of the commercially available foods.
What issues come with soil? I have always used gravel and fake plants, and wanted to try live plants in with my corydoras.
Soil can be incredibly difficult work with in an aquarium. I’ve tried it in the past, and in my opinion the negatives far outweigh the benefits. To begin with, you need to find absolutely perfect soil, or it can leech all sorts of toxins into the water. Only high quality sterilized bagged soil will should be used. And then you have the problem of the soil becoming anaerobic. Unlike other substrates, its very easy for the soil to not receive enough oxygen and then bad bacteria takes over. This can be countered with Malaysian Trumpet snails, but even then you may still encounter this problem. If you get to this point, it is very bad for your fish.
Even if you find a way to find perfect soil, and prevent it from becoming anaerobic, many soils will leech large quantities of ammonia into the water for a period of weeks or months when you first use it. This can cause huge fish die offs, and even in heavily planted aquariums, the ammonia levels will often spike.
If you’re willing to work hard to get soil to work, it does make a great substrate for plants. But to be honest, you can be just as successful with any of the plant substrates for sale in fish stores, or even with gravel if you add fertilizer.
I have a fairly strong aqua one nautilus 800 filter and the bronze catfish seem to love planning in the current
How often should these fishes be fed?
As long as you don’t overdo it, you should be fine doing it once a day. Just make sure to give them a sinking food if they’re kept with other fish.
Fish should be fed every 2nd day. My albino Cory’s just had babies I didnt even notice the change in their behavior I was very surprised to find Fry I. My tank which have grown a bit so I don’t even know when their eags were laid or hatched, best filter is a canister doesn’t move the water much
My corydora has laid eggs on the filter in community tank they’ve been there 2 days n no dish has touched them if I look closely can c small black dogs in them but they’ve went a kinda browny colour what do I do?
There’s not much you can do in this situation. Unless you can remove the filter, then you just have to leave them and hope for the best.
I got up this morning after 3 days and they’re all gone been ate unfortunately
I’m sorry to hear that. Hopefully you’ll have better luck next time.
I meant no other fish have touched them neons and danios n other corys n black dots lol
catfish spawned on aquarium glass, after water change and cleaning algae from tank front. I use under gravel filters. Should these be turned down to reduce flow when eggs hatch? only the parents and a pair of Pokadot miniature cats have been left in the tank at this point.
You could turn it down, but lots could still be sucked up to their doom. If at all possible, I would add a sponge filter and turn off the undergravel filter until all the fry are large enough not to be in danger. But just make sure if you do that to keep checking on the water parameters in case you get a mini-cycle.
I tried it that way n the day they should of hatched the parents had ate them all that morning I take my eggs out put them in the bottom of a milk carton with a airstone in it and they’ll hatch just let it float in tank to keep temperature the same good luck I just had a fry of over 90
I’ve been breeding them in a 15long. I have an under gravel filter set-up. What I do after the eggs are laid, I remove the air stone and top piece from my filter, extend the filter tube above the water line, and have a sponge filter set up to flow into the top of the tube. What this does is reverse the flow thru my gravel, thereby still filtering my water. I just set up the air stone elsewhere in the tank to get maximum circulation. Once the fry are 1/2″ long, I revert back to my original set up.
I’ve noticed that the fry that “find” the sponge filters grow faster than the ones on the bottom. This also happens with the fry that “find” the algae that I purposely let grow on the back and sides of my breeding tank. I believe this is because there is always a constant source of food there. I usually start feeding powdered food (this is done by running flake food, shrimp pellets and freeze dried brine shrimp through the blender) on the 3rd day after the eggs are laid. 3 times a day. I do a partial water change (2.5gals) every 3rd or 4th day without vacuuming my gravel. I will vacuum my gravel once the fry are at least 1/2″ long.
I’ve never actually noticed this before, but I’m definitely going to watch for it going forward. It’s a good catch.
Robert; I’ve read most of your articles. Are you a “market” breeder? Myself, I do it as a hobbyist. I started breeding freshwater tropical in the early 60s. I have bred most “bread and butter” tropical plus quite a few harder ones. The “Cory Cats” seem to be the ones that profit the most from sponge filters. I have also seen this in other fish such as “Danios” and “White Clouds”, but not to the same margin of growth. I believe that “market breeders” have picked up on this, and that is why they use bare tanks and leave the “mulm” on the bottom.
I was a market breeder for a while, but it became to hard to compete with the giant fish farms. I just do it as a hobby now, and I definitely use sponge filters on all my breeding tanks. It helps the fry survive, and they’re definitely cheaper and sturdier.
Sponge filter and canister filter keep the water clear and safe for the fry no submerged pumps big no no these fish like calm water
I have one cory catfish in my tank an it just laid eggs should i get rid of the eggs or should i leave them dont have any male cory catfish but i have male fish in my tank can another male fertilize the eggs
Without any males, the eggs should be infertile. And I wouldn’t worry about doing anything about the eggs – the other fish should eat them.