How Many Cory Catfish Fit In A 10 Gallon Tank?

The Cory Catfish is a popular freshwater fish known by several names, including Corydoras catfish, Cory cat, and Cory fish. Corys are hardy with a peaceful temperament, which makes them great passive tank dwellers.

Cory Catfish are quite entertaining, and they are active swimmers that school in small community fish groups. 

You need a big enough tank for schooling behavior to keep many Cory Catfish. But how many Cory Catfish can fit into a 10-gallon tank? And what equipment do you need to ensure your Cories thrive?

How Many Cory Catfish Fit In A 10 Gallon Tank?

How Many Cory Catfish Fit In A 10 Gallon Tank

On average, Cory Catfish grow to 2.5 – 3 inches in size, with four inches the maximum for adult specimens. The minimum tank size that one Cory requires to live comfortably is 2 gallons. But these are schooling fish and need a group of five to six to prevent them from getting stressed. 

The rule of thumb is to have 2 or 3 gallons of water for one fish. 

Ideally, you will need at least 10 gallons for five to six fish.

Should your tank feel too big for your baby Cory’s size, bigger is better, as they will do well in decorated tanks. You can use any extra tank space to put plants or rocks.

It is safer to have a larger tank than a smaller one. Using a 15-gallon tank is usually recommended for Corys to thrive. With every Cory Catfish that you add to your collection, your tank size needs to increase by 3 to 4 gallons. To understand how to decide the number of fish in a tank, look at these guides to determine how many guppies and bettas you can keep in a 10-gallon tank.

How to Calculate the Number of Cory Catfish for a Fish Tank?

There are more than a hundred Cory Catfish species. Some of these are bigger than others. This table will help you determine how many of these popular Cory fish will fit in your 10-gallon tank to ensure that each of them has enough space to move around.

Cory Catfish TypesSize (in inches)Number of fish in a 10-gallon tank
Bronze Cory2.55 to 6
Dwarf Cory25 to 6
Pygmy Cory16 to 8
Albino Cory34 to 6
Skunk Cory34 to 6
Julii Cory2.5 to 35 to 6
Sterba’s Cory2.5 to 35 to 6
Emerald Cory34 to 6
Panda Cory25 to 6
Three stripes Cory2.5 5 to 6

All of these Cory Catfish have mild temperaments, so remember not to house them with aggressive fish or bullies. Similarly, do not house them with smaller fish either. Research carefully, and if possible, only add other species of Cory catfish to your tank instead of selecting a new species.

What Will Happen If You Add Too Many Cory Catfish? 

Keeping too many Cory catfish in your tank will damage their health. No fish does well in cramped spaces; if you overstock your tank, they will suffer greatly.

More fish means less space, more waste, increased aggression, and more risk of infections and diseases.

To ensure that your fish are well protected, keep them in smaller numbers if your tank is small.

Equipment You Might Need For Your 10 Gallon Tank

1. A 10-Gallon Tank

Tetra Complete LED Aquarium 10 Gallons

You will need a good quality 10-gallon tank to start. Many tank kits are available that include everything you might need to start your hobby! We love the Tetra Complete LED Aquarium 10 Gallons fish tank kit. It’s ideal for Cory Catfish.


  • Includes all the necessary equipment.
  • The low-profile full hood contains a vibrant cool white LED lighting system to glow-up your tank and show off your Cory Catfish beautifully. 
  • Set includes a water filter, filter cartridge, water conditioner, food sample, and fishnet—just add your Corrys. 


  • Affordable and inclusive system makes setting up your Cory tank really easy


  • Not much aesthetic appeal to the tank and basic finishing

2. Filter

Should you already have a 10-gallon tank, you will also need a separate filter to help keep your Cory Catfish happy and healthy in their new environment. 

A Cory Catfish tank’s filter must be powerful enough for a medium to fast water flow. Even though Corys are used to living in slow-moving streams and sometimes fast-moving water bodies, keep the filter on a weaker setting to let the water flow at a medium pace.

A lower power filter will do the job just fine.

The Tetra Whisper Internal Power Filter 5 Tetra Whisper Internal Power Filter 5 is a great filtration unit for a 10-gallon tank. It offers a medium-strength pump that will provide a tranquil circulation rate but will still clean your tank effectively.  


  • Pump and water filter in one
  • Aerates water 
  • Easy to mount on the side of the tank with the provided clip
  • Filter pad traps floating debris and any larger particles 
  • Can cycle 80 gallons per hour, which means it can cycle your tank 8 times per hour at maximum power
  • Biobag filter offers biological, chemical, and mechanical filtration
  • Great price


  • Quiet pump and filter
  • Effective cleaning power 
  • Flow rate adjustable 


  • May not work as well on odd-shaped aquariums or hang flush on a bowl-shaped tank

3. Lighting

MingDak Fish Aquarium Tank Light

Cory Catfish need moderate to normal lighting to thrive. Use standard lighting that mimics its natural environment. The Corys live in dark areas of vegetation and murky water or swamps in the wild, so the lighting should not be harsh on them. 

The MingDak Fish Aquarium Tank Light offers an incredible spectrum of light, which means you have a better chance of finding a color combination that will work well for your Cory Catfish. 


  • Available in different lengths to fit your tank dimensions
  • Can be submerged in water, mounted to the tank lid, behind the tank, and to the side for ambient lighting
  • 16 different light cycles to choose from
  • Automatic shut-off with the built-in timer
  • Fully insulated with an ingress protection of 68
  • Comes with a remote control, so you don’t have to risk touching the light in case of electrocution
  • Adjust the speed of color changes to create a tranquil environment for your Corys


  • The range of lights makes for a colorful display
  • Adust the light intensity to provide the best setting for your Cory fish


  • The suction cups for attachment don’t last as long

4. Heater

Orlushy Submersible Aquarium Heater

Cory Catfish need an ideal temperature between 70 to 78°F. If your home is chilly, especially in winter, consider getting a heater for your tank.

Heaters are inexpensive, especially those needed for smaller tanks, such as for a 10-gallon Cory fish tank. However, some heaters may suit your needs better than others. 

There are many small-sized heaters available for small tanks. Consider heaters that are fully or partially submersible, adjustable, and pre-set.

We love the Orlushy Submersible Aquarium Heater because it is perfect for 10-20 gallons and has a reasonable wattage at 100 watts. The great price is another win-win point.


  • Six-foot long power cord is great for practical considerations
  • Heater is seated in a 2 mm thick quartz glass tube that is crack-resistant
  • Precision temperature range from 68 to 89°F
  • Built-in thermometer to help track temperature rate
  • Temperature variance is less than a degree
  • Automatic shut-off to keep the tank at the desired temperature and prevent overheating


  • Sturdy construction limits the chance of breakage or electrocution 
  • Remote digital thermometer is a great way to track your tank’s temperature


  • At 100 watts of power, the heater can be costly to operate in energy consumption

Other equipment

Some aquarists also purchase other miscellaneous equipment, such as air pumps, to regulate water flow in the tank. An air pump is a good investment if you have a bigger tank, but it is not required for a small 10-gallon tank, as your filter provides enough aeration of the tank water.

If your heater doesn’t include a thermometer, you will need to purchase a separate thermometer to track the tank water temperature.

The tank will also need manual cleaning of the areas where the circulation doesn’t draw waste up to the filter. A basic siphon set will help clean your tank substrate effectively.

1. The Siphon Set

AREPK 10 Gallon Fish Tank cleaner

The AREPK 10 Gallon Fish Tank cleaner and Aquarium Water Changer Siphon offers a basic cleaning functionality. The tapered cleaning tube helps regulate suction power and increase the siphon cleaning power. 


  • Rubber squeeze trigger helps prime the filtration system
  • Suction tube carefully picks out masses of manure and fish wastes
  • Ideal for a 5-10 gallon tank
  • Flow control valve helps regulate suction


  • Different nozzles help cleaning 
  • Less chance of suctioning a fish
  • Cleans in hard to reach spots


  • Not made from the best materials, but it does work well

2. A Wave Maker

Hhygger Quiet Magnetic Aquarium Wave Maker

Since Cory fish love to occasionally swim into currents, such as from a river or stream in nature, it can be beneficial to have a wave maker to increase the current in sections of the tank. The hygger Quiet Magnetic Aquarium Wave Maker can really help produce a stronger current in small areas of the aquarium, allowing your Cory fish to explore and practice their swimming skills. 


  • The wave action is adjustable
  • Fully submersible pump 
  • External controller to help you easily select wave functions and power 
  • Minimal noise, which won’t upset the shy Cory fish
  • Propeller is covered to prevent accidental damage to a fish


  • Powerful magnetic mounting allows for attachment to any part of the aquarium
  • 4 types of waves and 8 speeds to choose from


  • Can create a stronger current than needed

Tank Conditions In 10-Gallon Tank For Cory Catfish

In its natural habitat, a Cory Catfish prefers living in a murky, heavily planted space for extra protection. The Cory is a bottom dweller fish that prefers fine sand. It avoids coarse gravel that can hurt its barbels and fins. 

Corys also inhabit waters with a high flow rate. Copy these characteristics into your tank.

These fish habitually come up to the surface to breathe occasionally, so leave some open space for them. Cory catfish like heavily planted tanks, but if their tanks are too full, they might have trouble breathing, so don’t overfill the water in their tank.

Cory Catfish are comfortable between 70 – 78 degrees F and thrive in slow-moving streams.

Balance the pH levels for Cory Catfish between 6.0 to 8.0. Their ideal water conditions are warm and almost neutral. Cory catfish cannot tolerate high levels of ammonia and nitrite. 

The proper water alkalinity of a Cory Catfish tank is 3 to 10dKH.

Wrapping Up

Cory Catfish are a great fish species to keep, even in community tanks. These fish are pretty social, non-aggressive, and have cheerful dispositions. 

They make for good tank companions, and they are low-maintenance. Corys are active, alert, and engaged and participate well in a community tank. With so many Cory species available, you will find one that suits your needs perfectly, whether you’re a beginner or an advanced-level aquarist!

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