I have three panda corys in my 20gal planted tank. But I noticed recently two of them are acting very strangely. One of them is constantly bothering and generally nudging the other and almost "waggling" its fins at it when it's side by side... I have never seen them act this way before, its only those two and the third one is left out of the activity. They'll swim along all together mostly, but it's only that particular pair that does this (i can recognize each one by the amount of black on their fins and the thickness of the stripes on the back of the tail and the stripes over their eyes) .. The one will just kinda swim along or lay there and let the one(always that one) nudge it and rub against it.. Is it breeding habits or maybe a dominance thing?? I know they aren't moster fish but I figured this would be the best place to find out information..