cory catfish and betta

Cory Catfish and Betta: Potential Scavenger Companion

Male bettas must always be kept apart, but are they destined to be loners? Well, the good news is that, as long as your betta is not aggressive, he will enjoy having a little company in his tank.

So, what species of fish make good tankmates for lonely betta?

In this article, we take a look at Corydoras catfish to see whether these whiskered wonders make good friends for your betta fish. First of all, let’s find out more about Corydoras catfish.

What is a Corydoras catfish?

Corydoras catfish can be found in every fish store and are a regular sight in most tropical aquariums where they fit in well with community setups. Corydoras are small, ranging in size from two to five inches in length.

There are 161 species of Corydoras catfish. These cute little fish originate in South America. There, they live in slow-moving waters and rivers thick with vegetation. Wild Corydoras catfish feed on morsels of food that they find in the substrate. They spend much of their time foraging, using their whiskery barbels to sift through the mud and sand.

Different Species

These seven species of Corydoras catfish, or corys as they are affectionately known by most fish keepers, are the most popular among aquarists, and all of them get along fine with bettas:

  • Bandit cory: The Bandit cory is easily identifiable by the black “mask” over his eyes. This species of cory is more sensitive to changes in water temperature than others of the species, so he’ll fit in well with your betta’s stable, temperate environment.
  • Bronze cory: The Bronze cory comes in a few color variations, including bronze, green, black, and albino. These are the most popular of all the cory species. Bronze corys are easy to keep but should always be kept in small schools.
  • Julii cory: The Julii cory has markings that consist of lines of unconnected spots. That’s the feature that differentiates the Julii from its kissing cousin, the Three Stripe Cory.
  • Three Stripe or Leopard cory: Three Stripe corys are often mistaken for Julii corys but can be distinguished by the pattern of spots on their head that are connected in a long string that looks like a maze.
  • Panda cory: The Panda cory is highly social, gets along with all peaceful fish species, and can also be kept in unheated tanks.
  • Peppered cory: Peppered corys are widely available in pet shops everywhere. These pretty, peaceful little fish get along with all species, except large aggressive types, including barbs.

Like all catfish, corys are bottom scavengers, vacuuming up scraps of uneaten food and other debris from the tank substrate. That makes them ideal tankmates for betta fish, who prefer to spend time at the surface of the water.

Corys are long-lived, often surviving for up to seven years, provided that the tank environment and water conditions are suitable.

Are Corydoras catfish aggressive?

When searching for a tankmate for your betta, a Corydoras catfish makes the ideal companion.

Bettas prefer to stay close to the top of the water, whereas corys are confirmed bottom dwellers. Corys are rather drab and plain with small, stubby fins. That’s not to say that they don’t have a great personality, it’s just that they’re not flashy fish. That’s great news for you, as it means that your betta is highly unlikely to attack the corys. In fact, he will probably pay them no notice at all.

These peaceful fish will never show aggression toward your betta. Corys are highly sociable, especially when kept in schools of their own kind, and they will enjoy foraging and feeding together on the bottom of your tank.

How to determine the gender of Corydoras catfish

It is possible for captive Corydoras catfish to breed if the conditions in the tank are right. If you’re hoping to breed from your corys, you’ll need to know that you’re buying a mixture of males and females, ideally at a ratio of two males to one female in the tank.

Unfortunately, it’s not easy to determine the sex of corys with 100% certainty until they have reached maturity. That said, there are a couple of giveaways to look out for:

Generally, if you buy a random school of six corys, there’s a 98.43% chance of getting at least one male and female pair.

If you’re wondering whether your male betta and female corys will breed, fear not! Bettas and Corydoras catfish are completely different species and are therefore biologically unable to breed. However, if you discover clusters of tiny eggs stuck to plant leaves or to the sides of the tank, it’s likely that your corys have spawned.

If the eggs do hatch, it’s probable that the fry will become lunch for your betta before they have a chance to mature. So, a population explosion is highly unlikely.

What water conditions are best for corys?

Corys are hardy fish and are very easy to keep. However, you must make sure that the water conditions in your betta tank are also suitable for the corys. Corys don’t appreciate very high or very low pH levels, which can cause stress over time.

Ideally, corys need a pH of between 7.0 to 7.8. As luck would have it, the perfect pH level for bettas is 7.0, making both species highly compatible in that regard. When it comes to water temperature, the ideal temperature for bettas is 780 Fahrenheit. The cory will be happy with a water temperature of between 70 and 780 Fahrenheit, so again, the two species are compatible here.

Although corys are happy rummaging around in the substrate, they do like clean water. So, you will need an efficient filtration system for your tank. Make sure that nitrate levels are low, as high levels of nitrate will stress the corys and may make them susceptible to disease. 

Ideally, the nitrate level in your tank should be 0ppm (parts per million), which is what you need for your betta too.

What kind of habitat is good for corys?

Bettas and corys both enjoy similar habitats, so you can be sure that your betta’s habitat will suit corys too. Remember that corys do best in small schools of four or five, so you will need a tank with a capacity of at least ten gallons to comfortably accommodate your fish.

When decorating your tank, make sure that you include plenty of live plants, which will make the environment feel more natural. Corys and bettas both love live plants! Create plenty of hiding places for your fish by adding rocks and driftwood to your display. Corys love to hide inside caves or among the fronds of plants, so include plenty of both to keep your fish happy in an environment that’s as close to what they would have in the wild. 

If you’re hoping that your corys will breed, you’ll need to include lots of flat-leaf plants in your tank decoration scheme too.

The substrate that you have in your tank must not have jagged edges. Corydoras catfish spend the vast majority of their time on the bottom of the tank, so anything sharp or too rough could damage the corys’ stomach, fins, and barbels. 

Corydoras catfish have whiskers, “barbels,” that they use for rummaging through the substrate in search of food. If you ever have reason to handle your corys, avoid touching the barbels, as they are extremely sharp and can inflict a nasty injury to your fingers.

Cover the top of the tank

Wild bettas jump between puddles of water during the dry season in search of food, new territory, and mates. Bettas are accomplished jumpers and may leap right out of your tank if you don’t include a lid or cover the tank top with a layer of fine-gauge mesh! 

Although Corydoras catfish don’t actually jump like your betta can, they do have a habit of swimming rapidly to the water’s surface to grab a bubble of air or a morsel of floating food. However, sometimes, the plucky cory swims too fast and may jump clean out of the tank altogether if you neglect to cover the top.

Betta fish and Corydoras catfish diets

Your Corydoras catfish will enjoy vacuuming up the remains of any food that your betta has dropped. And they will also eat plant matter. However, you will need to feed him too. Corys are omnivorous, meaning that they will thrive on a whole range of different foods and will happily survive on the same food as your betta. 

However, if you buy floating pellet food for your betta fish, you should also offer your Corydoras catfish some sinking wafers that are specially designed for bottom feeders. Corydoras catfish enjoy bloodworms too, so they will happily share those with your betta.

Feed your corys and your betta once or twice a day. Your fish should eat all the food they’re offered within a couple of minutes. Any longer than that, and it’s likely that you’re overfeeding your fish. 

Also, you should make one day of each week a “fast” day, when you don’t feed your fish at all. Fasting allows the betta’s digestive system to fully process any residual food that is contained within it. This prevents conditions such as bloat and swim bladder problems. The corys will be fine with a fasting day too. On fast days, the corys will indulge in their natural foraging behavior, eating whatever tasty morsels they can find in the tank substrate.

How to choose a Corydoras catfish

When you’re ready to add a few Corydoras catfishes to your tank, look for lively, active specimens that are swimming around their tank or busying themselves by rooting through the substrate searching for food. Avoid picking fish that have swollen bellies, are extremely thin, or have damaged scales, fins, or tails. All these are signs that the fish may be diseased, which could spell disaster for an established tank.

Ideally, you should start by putting any new fish that you bring home in a separate, quarantine tank before introducing them to your main aquarium setup. A quarantine tank is simply a small aquarium of around ten to 20 gallons that is set up with a filter system, heater, and lighting. You should also include some silk plants, a hideout, and perhaps a few aquarium ornaments too. 

In a quarantine tank, silk plants are a better choice than live ones. Live plants could introduce disease, snails, or other parasites into the tank. A hideout is essential to provide the fish with somewhere to chill-out. Plus, it reduces the likelihood of stress-related diseases, such as whitespot and fin rot from taking hold.

Keep your new fish in quarantine for at least a week. Provided that your new acquisitions show no signs of disease or ill-health, you can then introduce them to your main tank.

In summary

Corydoras catfish make the perfect companions for betta fish. These are placid fish that spend most of their time on the bottom of the tank, rummaging around in the substrate for leftover scraps of food.

Corydoras catfish and bettas are both happy in a tank that has a pH of 7.0 and a water temperature of 780 Fahrenheit. Both species are especially vulnerable to disease when the nitrate levels in the tank become too high. So try to keep the nitrate down to 0 ppm (parts per million).

Unlike male bettas, which must be kept alone, all species of Corydoras catfish prefer the company of their own kind. They are happiest in a small school of five or six fish. Remember to provide sinking wafers for your corys to complement what they eat through scavenging. That will ensure that your fish receive the levels of nutrition that they need to remain healthy.

The bottom line: Corydoras catfish make the perfect tank companions for a lonely betta fish!

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