Hi, I had 12 cardinal tetras in my 20 gl tank, for about 2 month now. They were thriving and everything was fine, water parameters always good because I'm very diligent with maintenance, but since yesterday afternoon 3 of them are gone missing. Only 9 are swimming about and even at feeding time the 3 didn't show up. I'm a bit perplexed. 3 in one shot ?
My tank is heavily planted so I can't spot them if they're hiding or dead by just looking. Tomorrow is maintenance day so I'm gonna have to drain water and shift stuff around to look for them.
What could it be that 3 of them are MIA all of a sudden?