ok so i have a 75 gallon tank in which is about 6 months old and all of a sudden my fish are dropping like flies. Every night i lose one more. Originalyy in my tank i had 2 tomato clownsand 2 lawnmowers. The other day i went out and bought, 7 baby green cromises, 2 false preculas, and 2 dimon gobies. I now have 1 tomato clown, 2 green cromises, 1 lawnmower, 1 precula, and 1 dimon gobie. The water peramitors all tested fine, and the fish all looked healthy and it just seems that the next day there is one less, and i see my hermets making a meal out of the dead fish. Now this morining i noticed on the 2 chromises that they have chunks missing out of their sides like they have been being eaten alive!!! what is going on? does anyone have any ideas?