So, heres my story....
Five days ago I visited my lfs and there were a tank full of Piranha. Knowing I had the room to house another two, I couldn't resist and brought two back home with me. After doing a water change and re-arranging the tanks furniture, the fish were introduced without any problems. Within the hour they were swimming together and then lined across the tank (what a great sight). I left them for 24 hours before feeding. I fed them Prawn, everyone ate and cleaned up. No problem. I fed them again last night with the same result. Great!
Now, I got up this morning to find one of the new ones half eaten, literally. Feeling disappointed I fished what was left of the body out of the tank only to find that it was a female full of eggs. I did a water change to remove leftover flesh, etc... I found that I was also syphoning eggs out of the tank.
My question here is purely out of curiosity. I'm wondering as to why the others would attack a pregnant female? Is it that she was removed from the tank from the father?