I've read this ng for several years and never posted. Now, I believe I
may have forgotten more than I ever learned and need some beginning
wisdom.

Recently put a new small pond in for a friend. It's about 350 gal,
veggie filter, mechanical filter and what will be a biological when it
makes. She does have city water with both chlorine and chlormine. I
treated both, treated water with conditioner, and added bacteria.

Ran the pond for three weeks and introduced three 3" goldfish. Two weeks
later no problem. She then added 3 small koi (from two sources) One died
the second day during the night (no apparant illness) and the second
died two days later having a 1/4" blood red spot on abdomen. Third and
gf are alive and active.

I checked water and PH is fine, no ammonia but nitrites are medium high.
I increased the air, salted at 1/2 tsp per 2 gal, did partial water
change with water treated for chlorine/chlormine. The pond has bog
plants, floaters and submerged.

Could the fish have been ill when purchased? I know the Nitrite level is
due to the natural biological bacteria not being balanced yet but still
could be lethal. My ponds use well water so I am not accustomed to
treating. Also think I have forgotten "start up" and the tears it
brings. 8-(

I am thinking of transferring water from my large ponds into her small
pond to start the process. My ponds are 7 years old, appear disease free
(crossing fingers every year) and balanced. I have read that you can
transfer water to start the balance faster.

Opinions??

Thanks,
Barb