How long were they together before the aggression started? It’s rare that two severums work in a tank. They’re best as singles or in groups to spread out the aggression. When you keep two, a dominant fish will almost always torment a submissive fish. This also happens with two females, a non-paired male and female, etc.
Also, your second fish is not a rotkeil/red shoulder, which is why you don’t see any red on it. It’s a commercially bred efasciatus.
Also, your second fish is not a rotkeil/red shoulder, which is why you don’t see any red on it. It’s a commercially bred efasciatus.