Help, one of my female swordtails died yesterday.
My tank is new, 125L, nitrate levels are ok (0.5ppm), 25 degrees. I
introduced 5 zebra danios 1 week after set up, then 2 female
swordtails & 1 male swordtail 1 week later.
On Wed morning I noticed one of the female swordtails didn't eat, by
Wed evening she was sluggish and spent most of her time hovering by
the filter (at ~45 degrees at various depths). I noticed she had 2
white patches on her back, ~2mm diamater. She didn't eat again Wed
night. Thurs morning she seemed a bit more lively but didn't really
eat. By Thurs evening she was again just hovering near the filter and
she had rapid gill movements. Over 30mins - 1hour she swam
occasionally very skittishly. Then 1 of the white patches on her back
turned red and she had about 5-10 mins of swimming uncontrollably
(backwards, upside-down etc) until she finally came to rest on a
piece of wood.
Is this likely to be an infection that will affect the whole tank (do
I need to get some treatment). None of the other fishes seem affected
yet but the other female swordtail did start hovering near the filter
yesterday evening, she's still eating fine though.
Help! Can I prevent this happening to the other fish?