Experience Keeping Corydoras on Sand vs Gravel

[LadyoftheLake]

I've seen the arguments for both gravel being fine and for sand being best. But what is your firsthand experience with this? have you actually experienced any problems? is so what were they and with what species on what substrate?

also have you personally observed any difference when dealing with larger vs smaller species?

[Paul]

Watch @Coryvideo from his collecting trip to Peru. He showed the sharp gravel they were finding cory’s on. Personally all my tanks have a gravel substrate and the cory’s are all fat and happy. 

[3vi1p3nguin]

Mine have always been on flourite, and I've never had any trouble

[Ben_RF]

I have kept them on flourite, sand, fine sand, inert gravel, eco complete, and so many other things over the years, and not once ever had a problem. 🙂 Hope that helps.  

[Eric W-Farmhouse Fish Room]

Problems, no, but I find it more fun to watch them sift through the sand.

[Andy's Fish Den]

I keep cories on pretty much every type of substrate available, sand, gravel, eco complete, flourite, bare bottom and not had any problems with their barbels. 

[Phill D]

I've never used sand. Not to say i haven't thought about it. But reading about how it can trap gasses or suffocate plant roots i decided not to. I know some coarse sand types can mitigate that. Personally i use a rounded gravel. When i was little i had an albino cory on gravel. Now, i was a kid, but i dont' remember it being an issue. Right now i have panda corys on a rounded gravel (activ-flora). There's a handful of more blocky pieces but overall its rounded. I've only had these pandas a few weeks and they're basically an inch long. But so far they're having no ill effects from being on gravel. I use wafers, they eat their fill, take a nap, wake up and graze again. I don't see any redness or irritation on their bellies or barbels and their behavior seems pretty normal for corys. I spend a lot of time watching them because i love watching fish like that. Tirelessly working and foraging around, investigating and looking for things. 

[Mitch_ScruffyCityAquatics]

My 75 gallon has cories. It has both gravel and sand. The cories do tend to stay on the sand more often than the gravel, but Insee them all over the tank. 
 

the main reason I did some sand was for me. I enjoy watching them dif around in the sand. I think they are fine with most any substrates that you might use. 

[Nataku]

Some years back I had a paleatus corydoras get themselves stuck head first in the gravel substrate and die because I didn't  find them in time to see if I could have pulled them out and saved them. Was not something I enjoyed coming home from work to find. That weekend I caught all the fish and tore the tank down to remove the gravel and put sand in.

So I don't keep corydoras on gravel personally, though I know many have done it successfully for years. I use BDBS or ecocomplete in all my current tanks, and while the ecocomplete is somewhat rough, the grain size is much smaller than gravel and I've yet to see a corydoras manage to get themselves stuck in either, despite their snuffling and rooting around in the substrate. So I don't  really know if that one was a fluke or if they could actually do that more often, but I'm not going to take the chance to find out. 

I've never kept any of the 'smaller' corydoras species so I don't have any input there. I've kept paleatus, aeneus, sterbai, brochis and two species that I'm currently not sure on, though one may be ambiacus or aggasizii. Either way, they're not small either, around the same size as the c. Aeneus.

[JRed]

I had a group of 8 paleatus in a 40 breeder with gravel with minimal issues, I had 2 pass a couple months ago but I believe it was an unrelated issue. I actually have the remaining 6 spawning on the glass but the plecos kept getting the eggs. Finally took the time to learn how to pull the eggs and was fortunate to get around 60 eggs a week ago and happy to state a high hatch rate. Planning on moving the group to a 20 by themselves but not sure what to use as substrate - will following this thread going forward. Thanks

[aquatoid]

I've had them with fine sand substrate only, and it seems they enjoy it. They go about the tank digging in the sand and sifting it through their gills. 

Personally, after that, I'd never have them with gravel.

[FrostiesFishes]

I don’t think gravel is bad for them and they will root around in gravel. but I think It looks cooler and probably a more Natural behavior when they are on sand. In my cory breeding setups that I would typically keep bare bottom. I have started to put some river rocks in a line so that I can attempt to keep sand on one half of the tank so they can root around.

[Alison]

I have a school of pygmy corys and my substrate is my eco complete. They are all fat, happy water derps and doing just fine. I ordered another larger air pump so I can my sponge filter/air stone and drop another just air stone in so they have farther to ride the bubbles.