My BP's do that, without banging the glass; wonder if its due to their heritage.Midas are great but inept predators. I knew a guy that had one that would pile the gravel up against the front glass so you would have to get close and look over the gravel to see the fish which would then slam the glass in an attempt to get you. He had a lot of fun laughing at first time visitors!
Sent from my Nexus 5 using MonsterAquariaNetwork App