What am I dealing with here?
Almost 7 weeks ago I bought a shoal of zebra and leopard danios and put them in my cycled 30 Gal
with 6 white skirt tetras. One of the Tetras mysteriously died about 2 weeks in. Water quality tested fine at that point. At about 5 weeks, the smallest of my leopard danios died. He was fine one day, the next he was hiding, the day after his back fin was completely missing and he died later that day. I thought it had to do with a temperature fluctuation because my thermometer failed off, so I felt bad but didn't think much of it. Water parameters tested fine then too. Yesterday, which is about 2 weeks later I noticed another leopard danio's tail was looking a bit ragged and he was hiding a bit. I took some photos to post and ask about it and then a few hour later he was dead. Now, the 3rd leopard danio has a tear in his tail....What gives?!? Do I have fin rot problem? Fungus? Bacteria? Bad batch of fish? I'm at a total loss.....
My current parameters are:
Nitrate = 5ppm (did a water change yesterday)
Nitrite = 0
Ammonia = 0
PH = 8.1
Temp = 76
I've posted the photos to see what people think....