All the other posts are correct; cories love digging and should be allowed to (it benefits you because it is really entertaining watching them plough through the substrate :grin2. They aren't usually strong enough to push very deep (depends on the cory and the type of sand) and my large powerful bronze cory can only get about 3/4 of an inch into my sand. Really, they don't go very deep and mostly forage on top (mine only goes so deep when I purposefully bury blood worms) and it doesn't affect the scape at all. The sand just ends up back where it started. Mixing of the sand is also helpful, given that it releases stagnant and trapped air that could cause problems.
They might flip some of the finer silt up into the water column the first few days, the filter will get those, and the rest will actually settle below the rest of the substrate... The biggest stuff ends up on top.
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.