That's because I think what you got were Amano shrimps not ghost shrimps. Amano tend to have a slight bluish color to them with reddish spots (which I see in your first picture) and a stripe down their back. They are true algae eaters not just debris scavangers. They also tend to get a bit bigger than the common ghost shrimps. My link should have a picture of some Amano shrimp.I payed $6 for 3Normally I research things before I buy, but this time I have no idea what happen ... Awesome (none chain) pet store here in NYC but you never know. O well, will do home work next time ...