Just Friday I went on a campout. When I got back, one of my female Lemon Tetras looked like it's mouth had just deteriorated. No white, grey, or anything. It's upper lip was missing. It's mouth/gill area is a less-than-normally transparent color with a white-ish tone to it. It hasn't been keeping up with the rest, but has been over to the side most of the time.
I have another female Lemon Tetra had a very badly ripped dorsal fin. Both males (2m,3f [I keep losing Lemon Tetras I buy from my LFS]) look fine. I suspect that they are the cause of this instance, and perhaps the missing upper lip also. The males are territorial towards each other mostly, but often they will be aggressive towards the females.
Today is when I became really concerned, and for good and tragic reason. I lost an appearently healthy lemon tetra female this morning. This is the only one that didn't have any injuries. Under close examination I cannot find any physical signs of injury.
I have heard that in the wild (and captivity unfortunately) Tetras will release a hormone/phermone (I can't remember which) that will alert other tetras in the area and cause them to move on. I am worried that perhaps the tetras feel trapped "with the sharks". They can't leave and with all the injuries and 1 unexpected death, I imagine that they are all in a panic.
I am going to do a rather large water change today. Another thing that makes me really
nervous is that I am "borrowing" my brother's (BlackGoldfish on here) thin Rubberlip Pleco to help with my "algae" problem. I really don't want his Plec to die from tetras dying and suddenly polluting the water.
Do I need to get rid of all the Lemon Tetras? I am certainly not
getting anymore because I am tired of them dying after I bring them home from my LFS (which is not a chain). Now I have water that has freaking out tetras in it who only have 4 members and possibly soon to be 3 or less.
What a nightmare. What do you guys think?