yeah mine arent all that active when the lights are on, but when i turn them off its a different story. i'll dump a net full of massivores in before i go to bed, and turn off the lights, and within 5-10 seconds they are on the prowl. All the other fish know to watch out when they are hunting, they search and swim very fast, and when any part of them brushes against a pellet they whip around and grab it, usually with a large mouthful of gravel too! very powerful eaters, i cant stress that enough!!