This topic always seems to come up. My take is that not all cory are created equal. This post is discussing panda cory and in the case of panda cory I strongly recommend a sandy, even silty substrate for them. But even more important than that is the pH levels.
If we are trying to match what they have in nature even sand isn't quite perfect. But for most of us we can't keep a tank healthy with the kind of substrate a cory really lives in.
You can see in this photo from their natural habitat that it is very silty and soft. The barbels we talk about wanting to protect are there to help them find food in that environment.
The issue of gravel really depends on what kind of gravel. There are some gravel types (small grained, polished round) that cory do find with. But those types are nearly sand anyway. Your typical aquarium gravel is too sharp and tool large.
If we are trying to match what they have in nature even sand isn't quite perfect. But for most of us we can't keep a tank healthy with the kind of substrate a cory really lives in.
You can see in this photo from their natural habitat that it is very silty and soft. The barbels we talk about wanting to protect are there to help them find food in that environment.
The issue of gravel really depends on what kind of gravel. There are some gravel types (small grained, polished round) that cory do find with. But those types are nearly sand anyway. Your typical aquarium gravel is too sharp and tool large.
