Here's a brief rundown on what happened:
I had a new 10 gal
tank setup (now 5 weeks old), and cycled it with 2 1" fantails (one a Ryukin, the other a pearl scale). On day 4, just about Ammonia peak, noticed ich spots all ove both fish, treated with Jungle's Ich Clear. Spots gone in 24 hrs, during which time both fish were active, etc.
Tank finished cycling about 3 weeks later, both fish fine.
4 days ago noted Ryukin lethargic, tank parameter fine. Next day, fish back to normal.
Day after that Pearl scale started to be lethargic, tank parameters still fine, changed 25% water just in case. Next day noted 3 small white spots on Pearl scale's tail, and tail also a bit ragged. Thought maybe ich is back, added Ich meds. Also of note, the Ryukin had been a bit aggressive over the few weeks, and was nipping at the pearl scale's tail, thought maybe this was the cause of ragged fin.
12 hrs after ich med in, pearl scale more active, but will not feed ... bad sign. But this is close to midnight, can't do much (where are the 24 Hr LFS
when you need them?)
In the morning, pearl scale near death, rapid breathing at bottom of tank, barely moving. Died shortly after.
Exam of fish - ragged fins (all, not just tail), gills congested, head almost looked like there was hemorrhage inside.
During all this time, the Ryukin is acting just fine. Water parameter had been perfect - temp 72F, pH 7.5, NH3
- nil, NO2
- nil, NO4 - barely detectable.
Although these are inexpensive fish, and I half expected to lose one or both during cycling, we kind of gotten attached to them over the month. Also it was a bit upsetting to lose a fish for no reason ... after all, they survived the cycling & the tank parameters had been stable for over a week.
I have 2 questions:
1. Any idea what caused the fish death? I don't think it was ich, didn't act like the first bout. Perhaps the fish was stressed by something & the ich spots were just secondary. Anyway, I am more interested in why, so I don't make the same mistake again.
2. I am now putting the tank on QT .. ie will not add another fish until I am sure there is nothing bad there. How long should I wait, assuming the Ryukin remains healthy?