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The great corydoras substrate debate

So at this point i've heard it both ways, corys have to have sand, and corys literally come from river beds filled with jagged stones.

But i'm kinda stuck. I sprung for eco complete substrate to help with a few live plants, but now i'm feeling skittish about putting in sterbai corys into that tank.

Should i be worried about the coyrdoras well being in an eco-complete tank?

Alternatively has anyone had success either mixing sand and eco complete, or creating specifically sandy areas in the tank to give the corys a place to hang out? Will they actually spend all their time in the sandy area or probably just go all over the place anyway?

I'd hate to have wasted the cash for 2 bags of eco complete, but i'd hate to hurt the corys for no reason even more.

Could use your thoughts here.

b considine

a dude playing a dude disguised as another dude
Staff member
Personally, I wouldn't. But you've already purchased the Eco-Complete, so it seems a moot point. As for mixing, the sand will sink to the bottom, leaving the Eco-Complete on top, so no benefit there. Any way you could use the Eco-Complete for just the planted area of your tank and use sand for the rest? That is, use the Eco for the back and sides, sand for the front/middle or somesuch. That way the corys have an area for digging that you know will be snout safe.



CCA Members
I actually cap eco complete with sand from time to time. You will get some of the eco on top a bit, but otherwise stays separated unless it’s disturbed


CCA Members
Staff member
I have flourite in one of my tanks and CANNOT keep any whiskered fish in there. Within weeks, their whiskers disappear and then they pass.


Staff member
I have a fluorite tank that cories do fine in (pygmaeus - mid water swimmers) and a stratum and sand tank they, well, tank in. I think that one may harbor some bacteria they are susceptible to.

Eco complete isn't very rough or jagged un my recollection- definitely smoother than fluorite. Give it a try. If you notice issues, move the fish. Alternatively, skip the sterbai and go for a mid-water cory like elegans.


CCA Members
It's been a while since I've kept Cories in a tank with full substrate, but I'd recommend mixing a softer substrate such as pool filter sand. In my experience eco complete can be sharp and I've actually had issues in the past with the substrate scratching glass, so it's not something I'd use for a bottom dweller substrate.

As MTS hits everyone you will probably find a use for the eco complete in another setup, but if not just mix it. As Freakgecko said, it won't settle to the bottom without constant agitation. If you're tank vibrates due to a wonky filter or has a strong vibration from air pumps giving the stand a wobble, then you might see separation over time, but not quickly.