I think the problem is... there's an ongoing argument about it. Many on the site (myself included) will only ever use smooth, small grained sand. Others swear up and down that cories do fine in gravel. _________________ Dumpster Tank Nano Fish Mbuna
Honestly IMO they do fine in all substrates. I kept cories in all kinds of different substrates over the years with no damage to any of their barbels. _________________ "Feminae bene moratea historiam raro faciunt"
I think Cories do prefer sand but I think they do not have physical problems with gravel as long as it is not a sharp gravel like pebbles or river stones. I have kept them on sand and gravel and they do seem to prefer the sand when they are resting but when its feeding time they go to the gravels side of the tank. maybe because food gets lodged between rocks? but I do agree that it shold be a sticky _________________ In the End, we will remember not the words of our enemies, but the silence of our friends. - Martin
Posted: 2011.02.22(Tue)9:28 Post subject: Sand vs. Gravel for Corydoras.
In the endless debate of Sand vs. Gravel, many things need to be considered. It would be very helpful if folks who have used gravel tanks with Corydoras would give the exact details of their situation.
An experienced hobbyist using gravel with corys is a totally different proposition than a newbie who wants to set up a cory tank for the first time.
I'd want to know:
What kind of gravel? Silica sand, cushed coral, what?
What is the average size of each piece? (in mm)
How deep is the gravel bed? (in cm)
How long have these particular corys been on this gravel?
I'd ask about maintenance:
How often are water changes?
Do you use a siphon (gravel vacuum) at each water change?
Is the gravel siphoned at each water change?
How carefully, if at all?
If a siphon is NOT used how deep is your mulm bed?
It's not necessarily critical to use a heavy siphon at each water change.
Mulm is quite important to Corydoras health, and it's not a bad idea to let it build up a little, especially in an otherwise clean tank.
I'd wonder how they know the barbels are healthy. There are several photos of very healthy corys on this website, and a photo comparison might be helpful.
Corydoras size is very important, much more important than folks think. The Corydoras size in relationship to the tank is quite important, and Corydoras size in relationship to the gravel size is even more important. I can't stress this enough because it's not what you might think!
Large corys on smallish gravel is NOT as good as large cories on larger gravel, assuming gravel is used at all. If large corys are to be on gravel, then the gravel should either be quite large or extremely tiny.
I think Cories do prefer sand but I think they do not have physical problems with gravel as long as it is not a sharp gravel like pebbles or river stones.
This quote from Fifty is what everyone thinks, but it's only partially true! People forget that it is not just the sharpness of the gravel that's a problem, but the effort of shoving gravel around at all. If you use gravel or river stones too large for even the largest corys to push, you might be better off than if you use medium size gravel.
Very tiny gravel, like that which Dusko uses (some European brand) or some of the expensive substrates by CaribSea, such as Peace River or Torpedo Beach, are so fine and smooth that I am sure the larger corys would do well on them, assuming tank maintenance is up to par.
Very small corys, like the dwarf varieties - C. habrosus, C. pygmaeus, C. hastatus - will be all right on medium size gravel if it is maintained meticulously. The gravel is too large for them to push easily, and they don't try hard. In such a tank, there should be lots of other smooth surfaces, such as large plant leaves, leaf litter, wood, and other decor for them to cruise.
Taking it just from the point of view of comfort for the Corydoras, it's quite obvious that they would be much more comfortable on a smooth sand bed than on a gravel bed of any size. What would you rather sleep on?
As well as that, sand is fun to rummage around in, thrash around in, and shoot out your gills. If you were a cory you'd prefer sand, trust me.
That said, we have to consider the argument for gravel, which is why I posted as I did above.
I will probably end up copying and pasting this elsewhere with amendments as the topic continues to rear its head.
ps: I can easily make this topic a Sticky but, honestly, I don't think folks like to read stickies! _________________
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