How do I keep corydoras from digging up soil?

[MartinXIX]

My cories keep bringing up the aquarium soil under my plants. Any ideas how to keep the sand above the soil? I'd prefer not have to keep digging around the tank every week.
Edit: added photo

 

[RedOnion]

My cories keep bringing up the aquarium soil under my plants. Any ideas how to keep the sand above the soil? I'd prefer not have to keep digging around the tank every week.
Edit: added photo

How thick is your sand cap? Just saw the pic, honestly dont really know a solution. Was the sand always covering the soil?

 

[MartinXIX]

Edit: added photo

How thick is your sand cap?

The front of the tank is about an inch thick. Middle and back are just sprinkled over. I'm considering buying more sand but if I add an in over the mid and back I'm worried about pockets of gass buildup.

 

[RedOnion]

Edit: added photo

The front of the tank is about an inch thick. Middle and back are just sprinkled over. I'm considering buying more sand but if I add an in over the mid and back I'm worried about pockets of gass buildup.

I dont think any gas would build up as long as you have laid it evenly and stir it up every once in a while. But I am no expert.

 

[JTW]

Edit: added photo

The front of the tank is about an inch thick. Middle and back are just sprinkled over. I'm considering buying more sand but if I add an in over the mid and back I'm worried about pockets of gass buildup.

I'm of the opinion that the fear of gas pockets in sand substrates is largely overblown. You hear lots of people talk about it, but its rare that you run into a confirmed case.

Is it possible? Sure probably. But it is likely to happen? I don't think so. Especially not in a planted tank with lots of roots in the substrate. If you want some extra insurance, get Malaysian trumpet snails.

 

[Mcasella]

Don't get mts, just grab some assassins and keep them fed (they move through substrate but aren't anywhere near as hard to get rid of like trumpet snails).
More sand will help, the cories should keep the surface stirred for you.

 

[MartinXIX]

Thanks all. I think I'll buy another 20lbs of sand then add it this weekend when I service the tank. I'd get an assasin snail but I'm worried it'll eventually go after some of my small nerites. Between the cories, cherry shrimp, nerites, and controlled ramshorn population maybe I shouldn't worry about the gas too much.
I guess the only thing I need to know now is should I keep the fish in the tank while I add the substrate or take them out before that?

 

[ystrout]

I don't think gas buildup will be an issue. I just disturb my sand by stirring it up with a fork or kebob stick every time you I a water change.

Cories will dig and sift the substrate. It's just part of the way they look for food and play.