One of my girls had the same issues as yours - she was showing marked SBD symptoms after a couple days in the sorority. The first time I took her out of the big tank for a few days until she was swimming normally again. It happened again a few days after I returned her to the big tank, but not as extreme as the first time...a slight floatiness as opposed to "Stuck at the top." The second time I just kept an eye on her but left her in the big tank. After a couple days the symptoms went away and have not returned.
These things can be overcome
The Boy Feesh: Indigo CT, Lavatail CT, Ghost CT, Chicory HM, Redfish VT, Magic DT
The Girl Feesh: Christmas CT, Shine VT, Snowflake CT, Stripes VT, Midnight CT, Grif VT, Tangerine VT, Wraith CT, Amethyst VT, Ice CT, Poe CT, Turquoise II CT