Yesterday i did a pretty significant water change- replaced 3 gallons of my 12 gallon nano. (natural seawater). Well, I have a small group of brown yumas that I have had for about 4 months, and right after the water change, half of one of them blew up like a balloon, like it took in a bunch of water. It released the water slowly and was back to normal in about 2 minutes. I have never seen this happen before. It's back to normal now, everythings fine. Anyone know what that is all about?