recently i've artificially hatch a large batch of balloon ram's eggs...however,i have some worries bout the frys! about 60% of the frys seems to stay on tops of the tanks-on the surface! i wonder y this is happening...the ph is around 6.0 to 6.5! i try to make them swims down but then...it came back up again..almost all accumulating one one corner!! it doesnt seems be breathing heavily like those fish in lack-oxygen water...it just 'up'!! Y? Y?