I have recently bought I young Firemouth who is around 2 inches, it seems quite shy and stays in around its cave which I expect as its new, is has just started to dig a pit in the sand in its cave and whenever a BA tetra swims into the cave the Firemouth will chase it back out the entrance, I am wondering if this is normal behavior and could it be it is building a nest? There is currently just the one Firemouth in the tank and I am under the impression it’s a Male as it has pointed dorsal and anal fins, thanks.