Knight Gobies Aggresive?

[Icedcoldmine]

So...... My how big are knight goby territories? I have 2F and 1M knight gobies and the male relentlessly attacks my sailfin mollies who are double his size for no apparent reason........ he leaves my swordtails and f8 puffers alone who are smaller then him and are always zooming by....... are knight gobies always this annoying? Or is it just this one who is being a bully towards my sailfin mollies?

 

[Chockful O Phail]

Could be it recognized the threat the larger mollies pose to any offspring it could produce. When preparing to spawn/mate a lot of animals male or female will try to create an area of space around themselves to maximize safety of offspring.