Pygmy cory catfish (Corydoras pygmaeus) are a popular addition to home aquariums due to their small size, peaceful temperament, and active nature. These little catfish have a distinct behavior of schooling together in tight-knit groups, which is both fascinating to observe and important for their wellbeing in captivity.
What is Schooling Behavior?
Schooling refers to fish swimming closely together in a coordinated and polarized manner, moving in synchrony as a group. Schooling serves several key functions for fish species that exhibit this behavior:
Safety in Numbers
Schooling provides protection from predators that may have difficulty singling out and catching one fish from a large, fast-moving group. There is also safety in numbers when foraging, as a group can better watch for dangers.
Social Benefits
Many schooling species are highly social and require interaction with others of their own kind. Schooling allows them to communicate, develop social hierarchies, and exhibit natural behaviors.
Hydrodynamic Advantages
Moving together in a coordinated fashion allows schooling fish to become more streamlined in the water, expending less energy while swimming. Members towards the back of the group can draft off of the leaders.
Do Pygmy Cories School?
Yes, pygmy cory catfish are known to be schooling fish. In the wild, they would naturally live in large schools together. Schooling comes innately to them and is important for their health and natural behaviors. Unlike some schooling species that may gather loosely, pygmy cories form polarized, tightly-knit schools with all members facing the same direction and moving in synchronization.
A minimum of six pygmy cories is recommended to see their schooling behavior, but more is better. Larger groups of 8-12 create an impressive school that is active and entertaining to watch in home tanks.
Keeping Pygmy Cories in Groups
To keep pygmy cory catfish happy and exhibiting their natural schooling behaviors, it’s essential to provide proper care for the group:
Tank Size
A 20 gallon or larger aquarium with plenty of horizontal swimming space is ideal for a group of pygmy cories. This allows them adequate room to swim as an active school across the tank.
Water Parameters
Pygmy cories originate from the slow-moving waters of South America and require similar conditions. Water should be soft and acidic with a pH between 6.5-7.0, a hardness of 2-10 dGH, and a temperature between 72-82°F. Good filtration and weekly water changes are a must.
Tankmates
Pygmy cories are peaceful fish suitable for community aquariums. Avoid aggressive species that could pester, nip fins, or outcompete them for food. Some good tankmates include small tetras, rasboras, hatchetfish, dwarf cichlids, and invertebrates like snails and shrimp.
Cover
Ensure the tank has areas of thick planting, rock caves, driftwood pieces, etc. where the pygmy cory school can take refuge if they feel threatened. Open areas are also needed for active schooling.
Substrate
A smooth, fine-grain sand bottom is ideal. Sharp gravel can damage their sensitive underside barbels and make it difficult for them to sift and forage properly.
Feeding
In addition to algae-based supplements and sinking pellets/granules, provide a varied diet with plenty of meaty live and frozen foods. This helps bring out their energetic schooling at feeding time as they excitedly dash about together.
Conclusion
The distinct schooling behavior exhibited by pygmy cory catfish is innate natural behavior essential to their health, functioning, and quality of life. By providing proper tank conditions and keeping them in adequate-sized schools of 6+ individuals, pygmy cories will happily school together, entertaining you for hours with their social antics! Seeing a tight-knit group exhibiting synchronized movements brings out their best behaviors.
FAQ About Pygmy Cory Schools
Here are answers to some frequently asked questions about keeping pygmy cory catfish in properly-sized schools:
How many pygmy cories should be kept together?
A minimum of 6 is recommended, but groups of 8-12 pygmy cories allows them to form a nicely sized school that brings out more natural behaviors.
Will pygmy cories school with other cory species?
While they may loosely shoal with smaller cory species, only other pygmy cories allow them to form their characteristic tight-knit schools. Keeping a single species school is best.
Do I need to add pygmy cories all at once when stocking?
It’s best to add at least 6 individuals at once if possible so they can form a school right away. Adding smaller groups over time can work too. New individuals will eventually join the existing school.
Should my pygmy cory school have more males or females?
The gender ratio isn’t too important, but having a mix of both sexes may promote breeding and other natural behaviors associated with courtship displays in the school.
How much space does a pygmy cory school need?
Allow at least 20 gallons, with plenty of horizontal swimming room. This allows them space to exhibit their active schooling behaviors across the tank. More space is always better!