Fin rotting away and gills red after injury

[Lord Lamington]

Hi,

I had a guppy giving birth on Monday (bluegrass) and caught it to put into a birthing tank. Problem is, whilst catching it, it got caught between the wire side of the net and the glass and I accidentally squished it a little. It lost movement of its dorsal on its left side. I put it into the birthing container and it gave birth. Given its injuries, I left it in that tank until today and put it back into the top tank. After closer inspection, it appears as though the gills on the injured side are inflamed and red/purple, and the fin on that side has rotted away. It is interested in food although spits most out again. Is this an injury healing thing, or a its going to die thing?

Thanks