Over the past 6 months I have purchased two pistol shrimp and two different goby variety to pair with them. In both cases the pair would come up missing within days. This led me to believe either acclimation hadn't gone well or that there was a predator in my tank that was making a very expensive dinner out of my fish and shrimp. Well last night I was doing a little late night flash light examination and found my red banded goby that I bought almost 4 months ago...but the weird thing...I found him in the SUMP! He had to have ridden the overflow, got shot through a ball valve and then gone over a baffle in the sump to get to the return chamber. I have no idea how long he has been there, but I think it has been several months. Weird...now I get to go fish him out and put him back in the tank for another try at life WITHIN the aquarium. Wish me luck.