Cory Catfish Acting Strange

It's the gravel. Corys need a soft sand substrate. Bacteria on gravel can erode their barbels. The best thing to do is change the substrate to a soft sand. You can get Quikrete play sand in most hardware stores and it's perfect. Argos play sand if you're in the UK.

Corys should also be in a shoal. Minimum of 6. But it should be 10-12. When they aren't, they're stressed and stress makes them more vulnerable to other conditions.

Fish_owner23 said:

Thank you so much for this!! I will make sure to change it as soon as possible

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Roughly one pound of sand per gallon will give you about an inch of sand. I don't know if you plan on adding live plants or not. If not, then one inch would be fine.
It helps if you wash the sand first. To do that, put some in a 5 gallon bucket. Fill it up to about a quarter or 1/3 full. Fill the bucket with water and then stir up the sand. Pour out the cloudy water. (Do this outside in the yard, not down a drain). Repeat this until the water is relatively clear when you stir it up.
There are aquarium sands out there. But the Quikrete play sand is much cheaper and is perfect for corys and other bottom dwellers. It looks natural too, which is important for the fish. They get stressed out by sand that is white, black or unnatural colors because they stand out too much against it.