Hi, I'm new to the hobbie, and two months ago I received a new aquarium (160L/42 gallon) from a friend. The aquarium had a mbuna, a small koi and a pleco. I separeted the koi, and after some time introduce more 6 mbunas. But the last weeks they started dying all of the sudden. I thought It was the pleco since it's very big (25 cm/10 inches), and started feeding it more. Still, they kept dying. Can someone help me? I dont know what to do, they dont show any signs of disease and water conditions are fine.
pH: 8
Amonia and nitrate: zero
GH: 8
Temp: 28°C/ 82°F
pH: 8
Amonia and nitrate: zero
GH: 8
Temp: 28°C/ 82°F