nry said:
Everything I read suggests the whole 'cory's don't like gravel' is a myth, they come from all around the world across a widely mixed choice of substrate in nature. I've had them on gravel, sand, EcoComplete (which is actually quite rough) and they've all been fine.
They tend to generalise suggestions that are true.
Corys are silt sifters and therefore smaller grained substrates are best, the smoother the better.
Sand is ideal for them and you will see them display their natural feeding behaviour sifting the sand through their gills.
With small grain gravel they won't display their sand sifting anymore so you aren't seeing their natural behaviour. However they will be able to move the substrate around.
Larger gravel they won't be able to move around.
Coarse is a 'questionable' statement. all substrate including sand has sharp edges and is coarse if you look at it close enough. there is no such thing as a perfectly smooth substrate grain. The problem with obviously sharp grained substrates is that the Corys barbels become worn and they are very prone to infection as they are constantly digging into the dirty substrate (there is no such thing as a clean substrate.)
So what they should actually be saying is if you want to see corys displaying their natural behaviour then you want a tiny grain substrate like sand.
If you read Eco-Complete's statement on their product it actually states 'not suitable for soft bellied fish'. this is again open to question. Which fish are 'soft bellied?'
So in summary if you have eco-complete or 103mm gravel, then corys will be fine and shouldn'tBUT they won't be behaving naturally which is after all what we want really.
Doesn't have to be sand but it does have to be minute grain for them to fully behave as they would in nature.
They aren't like us. Take a city boy to live in the country for a year and after the novelty wears off he complains its too quiet. Take a country boy into the city and after the novelty wears off he complains about the noise. Put a fish into any situation and they make the best out of what is provided. They have no voice
🙂
AC