I have these two convicts in the corner of my tank and their shifting rocks and making a pit ?

Question

are they breeding cause there chasing the other fish away

Answer 1

They may be breading if not that is their space.

Answer 2

Yes they are breeding... or at least preparing a nest.  It's kinda fun to watch the pick up each little piece of gravel and spit it outside the nest.

Be careful of what other fish are there with them.  At times they can become quite aggressive and bite or even kill a much smaller fish.  So they usually require quite a bit of room.  Ideally a breeding pair should have 20-25 gallons, and they'll make babies like crazy.  

They'll personally thank you if you place a small saucer inside the depression they've dug.  I've done that so I could more easily monitor cleanliness.

Answer 3

Yes they are definitely breeding.