Now I have read in many places that if you have more than one green or yellow goby in a tank they will fight. Since I have not been able to get any other of the clown species in in this area I am think I might have to double up to get a few more fish in the tank. I did have two yellow in there at one time and the bigger picked on the smaller but I think that may have just been his character trait because when I moved him to another tank he picked on a 2" false percula until he got batted down. What are people's experiences?