Help breeding Pelvichromis Taeniatus 'nigerian red'?

[Mike Wise]

To me it looks too bare. Part of a krib's spawning ritual is moving sand away from the breeding site, actually digging a spawning cave. I'm not sure of the size of the tank. Is this the 40L(iter), 30 gallon or 55?

 

[justEpico]

To me it looks too bare. Part of a krib's spawning ritual is moving sand away from the breeding site, actually digging a spawning cave. I'm not sure of the size of the tank. Is this the 40L(iter), 30 gallon or 55?

This is the 30 gallon, sorry for not making it clear. The 40L is the first tank I showed you.