I have 8 Corydoras aeneus in assortment of sizes. I know they do best in numbers of 5 or more. In large groups you really get to enjoy them. But not the case with mine. Hardly ever seen during the day, either hiding under the slate rocks, under the driftwood, or in the plants. When its feeding time there on there patrol looking for food, along with searching a few times a day. They are more active during the night, more like what everyone expects from corys. Is this normal or are they still adjusting? They have been in the tank for a few weeks now.