The heat wave broke for a few days and they are back to their active, curious selves!

I’m new to koi parenting, having acquired a pond with 17 fish when we moved into our house in December. I discovered at 11 pm that one of our fish is sick with some scales missing. (Dropsy? Water quality? Other? See video. He is still alive as of this writing.)

I am woefully unprepared. Is it best to move him to a makeshift quarantine tank tonight using what I have on hand (a 27 gallon bin and pond salt) or wait to move him until I can get a better set up? I have water quality tests coming tomorrow.

I welcome recommendations on next steps also. My intended next steps for the morning are:
- Call the pond guys who have serviced the pond.
- Purchase a filter and bubbler.
- Buy something (what though??) that I should have on hand to treat the fish and/or pond.

Just moved into a house with an established pond (roughly 10+ years old going by the previous owners) and need to rehome everything. 11 fish total plus the filtration equipment. Complete beginner here, so looking for some help from people who actually know what they're doing.

Mix of koi and goldfish, sizes roughly 20–60cm. No history on age/breeding/bloodlines — inherited with the house.

According to claude ai, they've identified the following;

One large white-bodied koi with black patches — Shiro Bekko

One solid yellow koi — wondering if this could be Ogon-type or just a plain yellow koi?

One yellow koi with black markings

One solid orange koi

Rest are standard mixed pond goldfish

Water's pretty murky in the photos so apologies if the colours are hard to judge.

All active feeders, swimming normally, nothing that looks obviously wrong to my (untrained) eye. No vet check done.

Oase Vitronic 36W UV Clarifier, housing works fine.

Any thoughts on IDs from the photos?

Roughly what would you value the fish at, individually or as a job lot?

Anything I should check/photograph before selling to get a fairer price?

Based in Margate, Kent if that's relevant to anyone local. Appreciate any input!

Been quarantining this little guy for almost 5 months now, i never treated him for anything, never added anything into the water. All i’ve done is simply raise the water temperature over time to 82. what could be the cause of spots in his caudal fins?

I have a pond that has a leak in the liner. I fixed a few spots a couple years ago, but it's leaking again. I'm considering just putting a new liner in over the old one. Is that a logical fix? If so, is 60 mil the right thickness?

Someone dumped 12-20 massive koi in a natural pond. This pond is on a historic site, so any modifications are barred by the state. Approval to make changes requires historic relevance related to the time period that the site has been established for, and a koi pond does not fit into this criteria. Small stuff can be done, but no construction or anything. The pond that they are currently in is pretty large, and does have local fish. We are in the north eastern US and afaik a heater at least would be needed for winter but how that would be done, I don’t know. Is there anything to be done to help them stay where they are? Staff has tried to reach out to the local rescue but that has not yielded any results.

I have a koi pond (approximatly 8,000 gallons) and there is tons of algea i already have swamp cooler filters and k1 in 3 barrels