I have 4 Bala sharks at the Moment in a 75 Gallon tank they are only 3 1/2 -4 in tight now , For some reason two of them keep coming alongside each other and then start to smack each others bodies together over and over everyday almost all day. There are cory Cats at the bottom Layer , and a Two little cichlids that's all. Why Do you think they are doing this???I can't find a specific answer online at all. Thank you, I'm new here. Lennie 🦈🐟🦐🦐 I have a 30 Gallon filled with Cherry Shrimp prob a 1000 or more, Started with 4 Shrimp. Amazing.