Last Updated on August 1, 2022 by cmoarz
Corydoras are one of my favorite fish to have in my aquarium. They are also one of the first fish I ever got when I started aquarium keeping. When you first start taking care of corys in a tank, it’s important to see the signs of stress and/or illness so you can take care of them right away.
One of those potential signs of illness is hiding. So why do my cory catfish keep hiding and is it a sign of illness or not? Sometimes, Let’s get into why this behavior happens and how you can tell if your cory is just stressed or if there’s something else going on.
Why do my cory catfish keep hiding?
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corydoras hide for a lot of reasons. They are fairly skittish fish and can hide because they’re scared or stressed, or they could even be sick.
And other times, they could just be hiding as a natural part of their behavior. Corys are bottom-dwellers, so it’s natural for them to want to find a place to hide away from the light and potential predators.
So how can you tell the difference between a cory that’s just hiding because it’s stressed or one that’s sick?
Here are some signs to look for a potentially ill corydoras:
Your cory is hiding more than usual
If your cory is hiding more than it used to, that’s a potential sign that something is wrong. This could be because it’s sick or because it’s stressed.
If you’ve recently added new fish to the tank, that could be stressing out your cory and causing it to hide more. Corys are also sensitive to changes in water quality, so if there’s been a change in your tank’s water, that could be stressing your fish out and causing it to hide.
Your cory is not eating as much
If your cory is hiding and not eating as much as usual, that’s a sign that something might be wrong. When fish are sick, they often lose their appetite.
Your cory looks sick
If your cory looks sick, with sunken eyes or cloudy fins, that’s a sign that it might be ill. If you see any other changes in your cory’s appearance, like its body looking bloated, it could also be signs of illness.
Your cory is swimming erratically
If your cory is swimming erratically, that could be a sign of stress or illness. This is especially true if your cory is swimming quickly and darting around the tank (of course, sometimes they do this anyway so it’s not always a sign of illness.)
Your cory is gasping for air
If your cory is gasping for air at the surface of the water, that’s a sign that it might be ill. This could be because of a number of things, like parasites, bacteria, or a virus. It could also be a sign of a swim bladder infection and bad water parameters.
These are just some of the signs that your cory might be ill. If you see any of these signs, it’s important to try and figure out what the underlining cause is so you can treat your fish.
Your cory could be lonely
Another common issue a cory may be hiding more than usual is because they don’t have enough of their own species in the tank to feel comfortable.
Corydoras are shoaling fish and prefer to be in “schools”. So if you only have one or two corys in your tank, they may be hiding because they’re lonely.
If you think this might be the case, you can try adding more corys to your tank. You should have a minimum of 6 corydoras at any given time, of the same species.
Different species won’t interact the same way so it’s important that they are the same species. Adding more corydoras will usually make them feel more comfortable and they’ll start to come out more.
Just be sure your tank is large enough to accommodate the extra fish. Corydoras are small fish but they still need room to swim and hide. So a 20-gallon tank is a minimum size you should have for a group of corydoras.
The environment might not be right for them
Corydoras need specific substrates to feed on. In this case, it’s usually sand. Any rougher substrates can damage their barbels.
In fact, if you watch very carefully, you can see how the cory sifts the sands threw its mouth and expels it from the back of its gills while eating the food.
Of course, these are just signs your fish might be sick. The truth is corys also hide as a normal part of their behavior.
So it can be normal behavior for corydoras to hide?
It can be absolutely normal for your corydoras to hide away. Corydoras are nocturnal fish and prefer to be active at night. So during the day, it’s not unusual for them to find a place to hide away and rest.
This is especially true if you have bright lights in your tank. Corydoras are shy fish and don’t like a lot of light. So if your tank is brightly lit, it’s not surprising that your cory would want to find a place to hide.
Generally speaking, you should only be concerned if your cory is hiding more than usual or if it’s not eating. If you see either of these things, it’s a good idea to check for other signs of illness. But if your fish is just hiding away like normal, there’s no need to worry.
If you turn off your tank lights and lower the ambient light in the room, your cory will be more likely to come out and be active.
You can also try offering them food at night when they are more likely to be active. If they don’t eat the food, it’s not a big deal – they might just not be hungry.
But if you see them actively eating, that’s a good sign that they’re healthy and just behaving normally.
This is what you can do to make them a little more active
You can only do so much to make corydoras more active during the day, but there are a few things you can do to help spur them into action:
First, try changing the type of light you use in your corydora tank. A lower wattage, and duller light will make the corys feel more comfortable and less shy.
Second, try offering them food at night when they are more likely to be active. That way you can watch them feed without them being so skittish.
Third, try dimming the lights in the room so that the tank isn’t so brightly lit. This will make the corys feel more comfortable and they’ll be more likely to come out and be active.
Fourth, you can try adding some plants or other hiding places to your tank. This will give the corys places to hide during the day, and they’ll be more likely to come out when they feel safe. It sounds counterproductive to add more places for them to hide, but if they feel more secure in the fact they can dart away from danger, they’ll be more likely to come out during the day.
Finally, you can try adding more corydoras to your tank. This will make them feel more comfortable and they’ll be more likely to come out and be active. Remember, corys are social fish and prefer to live in groups. So a minimum of 6 corydoras is ideal.
Doing all of these things will help make your corydoras more active during the day. Just remember, it’s normal for them to be shy and to hide away during the day. So don’t be too concerned if you don’t see them out and about all the time.