I'm absolutely positive. I was looking at the tank and I saw he was HUGE. There is nothing else he could have eaten and unfortunately math tells me there is one fewer scrub. I DO separate them during feeding... and this event didn't occur during or right after feeding either. How much should 5 week old scrubs be eating...

I AM worried about the offender. While he/she is alive at the moment and pretty active, I'll be monitoring carefully during the day.