Using gravel for Corydoras can actually prove fairly harmful. You see, these bottom-feeders will root around in the soft, sandy substrate at the bottom of a sandbank or river (or in this case, tank).
Simply put, gravel for Corydoras is unsuitable for sifting through. Corys will often end up abrading and bruising themselves if they attempt to bottom-feed in the gravel. Their distinctive and precious barbells can even fall off (these are what they use to spear their prey, and to deter predators)!
The size of gravel in an aquarium will be the deciding factor if you should use it for you Corydoras catfish. If you use the wrong size aquarium gravel you could harm or injure your little catfish. Sand is the best option for catfish and especially smaller corydoras catfish. They love to move the sand or gravel around the bottom of the aquarium and sand offers less risk. It will not harm their mouth or jaw as it is too small to get trapped in their mouth.
Gravel for Corydoras is a Serious Health Risk
If you’re considering using gravel for Corydoras, you will want to know that this can prove a serious health risk. Corys may look tough with that outer ‘armor,’ but their skin is really quite sensitive when it comes to gravel! This rough substrate will abraid their skin, and bruise them, as well. Along with this, gravel tends to hold onto more bacteria than sand does, creating a greater chance that your Corys will get sick.
If exposed to gravel for too long, the distinctive Corydoras Catfish barbells will even weaken and fall off -a tragic loss. Never use sand in a Cory tank, so you can avoid this altogether.
Feeding Your Friendly Bottom Feeder
What is it that Corys are finding on the bottom of rivers and sandbanks, anyway? Worms, for one! Corydoras Catfish are omnivores and love to pick up bugs and organic detritus from where they fall or live down below.
This is why Corys likewise search the bottom of your tank. They will require sinking pellets in order to feed as they do naturally. They will also thank you for live food, such as mealworms, bloodworms, live shrimp, and the like! Just make sure that there is a nice, soft layer of sand for your Corys to graze (or, hunt) in.
Gravel for Corydoras Catfish is Unnatural
Corydoras Catfish can be found naturally in South America, especially in the small water tributaries and rivers of Brazil. Sandbanks are their favorite spots to linger. Even in the wild, fine sand is the substrate that works best for this bottom-feeder.
Their naturally ‘soft,’ sandy environment is likely why the skin of the Corydoras Catfish is not particularly thick. They would not have many sharp rocks or gravel around which to maneuver. This is why at-home it is so important to create an environment that will preserve their skin, as well.
We use Super Naturals sand from Amazon as it offers great value and is easier to get delivery straight to our door. Check the latest price here!
Sand is the Best Substrate for Corys to Have
So, what kind of substrate should Corydoras Catfish have at the bottom of their tank? Something very fine -even some sands are too abrasive! Silica sand is your best bet, and always white or beige in color, as this will help ensure the sand does not stain the water. Just remember: for the Corydoras Catfish, always provide sand, and never gravel.
Small Stones are Also Bad to Have in a Cory Tank
Corydoras Catfishes sure look imposing with all of that body armor. As it turns out, this is a lot of show! The truth is, scaleless fish such as the Corydoras Catfish tend to have skin that is much more vulnerable, in general. Their armored appearance serves merely to deter any likely predator. The often-toxic barbs also make the Corydoras Catfish rather tricky for predators to swallow!
Gentle Corys will also take harm from pebbles, no matter how small or smooth they are. These simply do not accommodate their barbells, and, like gravel, can cause the deceptively-fragile spines to fall off.
Keep Your Sand Super Clean
While bottom-feeders can help tidy up your tank, you should never depend on them for this entirely. Corys are actually used to circulating waters -rivers, creeks, streams- so stagnant water can hold bacteria that will make them sick.
The same goes for dirty sand, so this will need to be kept very clean, as well. You can use a gravel vacuum, which should also work great on sand rather than gravel.
As you can see, gravel for Corydoras Catfish is far from ideal. Fortunately, fine sand, such as silicon sand, is the perfect alternative! Sand will make filtering the substrate both safe and easy for your friendly bottom-feeder. Just make sure to keep the sand sparkly-clean, and your Cory should be free from risk!