Comething wrong with my Julli/leopard corys

[Jmoto]

I had 2 corys before and they were really active i had them for about a month and they were really active. someone told me they do better in groups. i decided to buy 2 more and then they all just stay still.

do you know whats wrong ?

 

[123justin]

When Corys are in groups, they become more relaxed. I had the same thing where 1 cory would swim all over the place but when i put in 3 more corys, they all chilled at the bottom of the gravel together in a small group.