t barbs acting wierd

[the wiz]

I have two t-barbs swimming upside down, wiggling like puppys all over the tank. The other two are fine. The two in question seem to be swollen. When I try and caught them they are fast as always and swim up right. They seem to try and get underneath plants and hard structures and hold their place upside down. Could they be trying to lay eggs. Had them almost two years and nothing like this before or with other T-barbs.

 

[tankman3]

Mine swim face down after feeding all the time and a couple are swollen looking..I've been wondering the same thing