It finally happened

My poor fingerlings.

10 of my current fishes were floating when I got home today evening. I believe it was due to stress and possible water condition. While doing up the IBC on Saturday, I noticed the fishes in the barrel tank showed sign of gasping for air. My siphon systems seemed to have developed a major issue thus the ebb and flow was not functioning properly.
I hastily replaced new filter and replenish 50% water which at that instance has turned murky green. I guess the combination of sudden new tank water at night might have affected the poor fingerlings. This has been by far the most number of fish losses at 10 in a day. Sadly most that have died seemed to be the female (smaller).