I recently bought two clownfish. They were both acclimated to the tank, eating and swimming around without signs of illness. This morning I found one of the fish sucked into the intake of one of the powerheads..dead. All water chemistry and salinity appears to be good. I checked the powerhead box and see no protective grate for the intake that I should have installed. I did shut off all lighting to the aquarium when I went to bed. Is there anything I could have done to prevent this mishap?? The other fish seems to be swimming around fine this morning....Thanks