With it only lasting five days, I don't think it was to be and it was nothing you did. I have two in a 200 and both came from smaller tanks where they did very well. As a matter of fact I think they did better in the smaller tanks, than the 200. A friend had one in a 29 and it doubled in size before moving it to his 125. My two eat FW Mysis, Mysis, Blood Worms, and Pods.