I have two Oscar fish one about 5-6” and one about 4” as well as two green turquoise Severums, a Chocolate and 4 Geophagus Sveni in a tank with a single male Kribensis. I am totally baffled that the Kribensis dominates the tank. The largest Oscar runs most of the tank but even he swims from the Kribensis when it decides he is too close to him. Anyone else ever see this behavior before? Water parameters are Ammonia 0, Nitrite 0, Nitrate 10 ppm. Water changes 40% weekly 6’ long tank with driftwood, rocks and hiding spaces. Java fern and anubias on the driftwood and rock.