Originally Posted by inuudo
Harlequin Rasboras aren't live bearing.
Is it possible that the one danio with the bubble on its side was overfed? I have recently experienced something similar with a guppy. It developed a bump on its right side just behind the pectoral fin; unfortunately, what I initially thought was a surface bump was actually food emerging from a perforation in its side.
The guppy behaved normally apart from that horror.
I don't think it's over feeding, my uncle feeds them very sparingly and since he's developed that bump, he swims a little slower and is usually the last to get to the food. They get fed a small pinch of tropical flakes once a day.