Spring prep for fish with ulcers

[MrsGriffin]

Hello from Northern Calif.

I need to know how to transition my pond to Spring without making my two sick koi any worse. I had taken the advise of all of you last year and treated the ulcers with tricide-neo, corrected the pond chemistry, added a larger filter and bigger pump, etc. The fish were looking better, although not perfect, but at least looked like they were healing over.

Now, the ulcers have spread on the one fish and are looking raw again, and the other has very red veins in her tail and fins. Also few red spots. Here are the current conditions:

We've had some wild weather swings... 79 the past three days, might snow tomorrow. Highs are back in the 50's for the next two weeks.
Water temp is currently 47
Salt is 0.05%
KH is 6 drops (sorry, I don't know what that equates to in pond terms)
the other parameters are in the photos attached.

My pond:
1444 gal
10,000 Oase bio filter
wine barrel bog filter/waterfall
2 stone aerators
1-2000 gph pump and 1-1200 gph pump
skimmer is not currently running

I have 2 large koi, 2 small koi, 1 goldfish

Here are my questions:
1. Is there anything I can add at this stage to help the ulcers/red fins.....
a) Medications? Salt?
b) If so, what? In what order? Frequency? Water changes in between?
c) At what point should I treat pond for parasites, if at all?
2. Should I be doing regular water changes at this time of year? How often?
3. I've read that some people have a steady small trickle, or daily dose of fresh water at all times, to keep PH stable. Any thoughts on that?
4. Anything I do the pond at this stage makes me nervous about PH crash. Anything else I can do to keep it stable?

Ok, that's enough for now. I can't tell you how valuable all of your advise has been!!!! Thank you in advance.

[RichToyBox]

"Here are my questions:
1. Is there anything I can add at this stage to help the ulcers/red fins.....
a) Medications? Salt?
b) If so, what? In what order? Frequency? Water changes in between?
c) At what point should I treat pond for parasites, if at all?
2. Should I be doing regular water changes at this time of year? How often?
3. I've read that some people have a steady small trickle, or daily dose of fresh water at all times, to keep PH stable. Any thoughts on that?
4. Anything I do the pond at this stage makes me nervous about PH crash. Anything else I can do to keep it stable?"

1. I really can't tell much about the ulcers, but they look like they have heeled, so I don't think I would do anything except keep an eye on them. If they get inflamed then it is an indication of infection and treatment will need to be done, preferably with the Tricide Neo. I would not add any treatments to the water unless there is more reason than this. Most parasite treatments can't be used when the water temperature is below 50*, so just keep an eye on the fish for now.

2. Water changes are always good. I am a firm believer in at least 10% per week. I would think that if you run the hose until the extremely cold water in the hose is expelled before putting water into the pond, the temperature of the pond will be affected very little. 10% of the difference between the cold tap water temperature and the pond temperature should probably be less than 1*. Be sure to use water treatment for the chlorine or chloramine.

3. Continuous trickle is good, but I like that to be from wells rather than city water supplies as city water has chlorine or chloramine and you don't know if the flow rate will overwhelm the ponds ability to neutralize those.

4. pH crashes occur when the KH is extremely low. If you have not been adding baking soda, then your water source appears to have sufficient KH that with the 10% water changes, you shouldn't have to worry about a pH crash. I would test the KH weekly and as long as it stays 6 drops or more, then you are good. If it drops to below 5 drops, then add baking soda to bring the KH back up above 6 drops. The filter bacteria produce acids that consume KH, so it is always going down and it is just a good practice to know what it is.

[MrsGriffin]

Thank you for this!
Just to make sure.... You don't think I should bring the salt up?

[RichToyBox]

If there are nitrites, use salt. If there is a large ulcer leading to dropsy symptoms, use salt. If there is evidence of ich, use salt. For anything else, don't bother. Koi are fresh water fish that will tolerate some salt, but do not need it or benefit from it most of the time.