Beat up goldfish

[Misskiwi67]

We just got a new pond set up, a 300 gallon stock pond actually. We put in 5 small fantail goldfish, and then a week later ended up adopting 8 6 inch comets from a nursing home. They were all doing great, but when I went out to feed them today, the comets are all beat up. Their tails and backs are all splotched with red, and their tails are pretty shredded. I caught a couple, and looked at them, and it doesn't look like septicemia, because its just on their back and tail. Nothing on their stomachs. Also, the fantails look great, nothing at all wrong with them. Any ideas what happened????

[anonapersona]

I'll venture a guess that the pond is too new, ammonia levels and /or nitrites are high. You've added too many, too fast.

Have you tested for ammonia? Nitrite?

I suggest water changes, 10% only, as you can't match temperature very well. But frequently. Daily.

And stop feeding the fish for about 3 days or more. This will ease the pollution. After that, feed only every other day,

Slowly add salt. I suggest Mortons' Pickling salt which has no YPS or iodine in it. Or Solar salt for water softeners. Dissolve before adding to the pond. For 300 gallons you want 6 cups, as I recall. Don't add it all at once, take 3 days to do this amount.

My tank is this size, and I did something just like this when I first started it up. Some bought fish then some rescued fish.

If this is so, you might be able to get some help from the place the other fish came from. Do they have any gravel or filter material that you can use to help cycle your filter? Add gravel or filter media to your filter -- you do have a filter don't you?
Any plants in pots that you can borrow for a week or two to get the bacteria established?

[Misskiwi67]

yes, there is pond filter for a 300 gallon pond. There are also the pots and lilies from the old pond. They weren't fed at all last week because my parents were out of town and I had to care for my moms birds. Water change is already done, and I'll keep them up until they're healed up. Thanks for the help.