Ammonia spike. Septicemia? HITH? Something else?

[Dvrich89]

Kind of long but any help is greatly appreciated....🙏🏼
 

55 gallon
Ammonia was .25-.5 and still is .25
Nitrite 0
Nitrate 5.0
Ph 7.4

I had an ammonia spike. (I’m doing water changes and have added prime)
A couple weeks ago my canister filter started leaking. I had to use my hang on back filter until I received the part to fix my canister. Once the part came I hooked my canister back up but I think I lost some beneficial bacteria in the process even though I put my sponges in the hang on back filter and the rest of the media inside the aquarium. The hang on back filter was a topfin 60. It didn’t move my water as well and my water started to develop an odor which it never had before. 
I have added charcoal and I've done a water change yesterday and today. Today I used some stress coat and prime. 

Yesterday after the water change they all shed their slime coats. They were twitching and shaking their heads(today too after water change). Today I noticed the red streaks, shown in the pics with arrows, which weren’t visible before. The red streaks are in dorsal and anal fins of the 2 koi’s too. The angel in pics #4-6 is looking white on top it’s head. I circled those areas. The 2 koi’s fins have also started to look cloudy/milky when they were completely clear a couple days ago. They are still eating. 

Is this just ammonia causing all the issues or is there more I need to be treating?? Septicemia, Columnaris, HITH? What do I do to save my fish? 🥺

white areas circled- not fuzzy or cottony, doesn’t look dented or like a crater either...

 

Edited December 10, 2020 by Dvrich89

[Colu]

It looks like ammonia burn  to me keep you with your  water changes  and add aquarium  salt 1table spoon  salt  for 2gallons replace salt after water change

[Colu]

Ammonia burns can cause red  streaks  and some of the symptoms your seeing  most important thing is to get your ammonia levels down I would start puting in seachem stability 

Edited December 10, 2020 by Colu

[Struggle]

How are the fish doing?

[Dvrich89]

@Struggle

first koi had a lot of red lines which have gotten better but now I noticed round white patches on the anal fin. It’s def not ich. It’s bigger, isn’t raised and not all perfect circles. 🤷🏻‍♀️
the second angel pictured now a small white protrusion under its pectoral fin but on the body. It also has the red lines. 

the last pic is the same koi in the first pic. It’s belly seems kind of sunken in? Maybe I’m being extra paranoid. They’re all eating great. Lethargic acting still. 
 

ammonia .25, nitrite 0 and nitrate 10-20

I’m still just performing water changes and using prime to detoxify the ammonia. Wondering if I should start a med? 

[Struggle]

Do any of them look like these? If so I have post on here how I treated it, I’m at work now and would find it if I had time. I’ll check back later this evening. Hopefully this helps out a little bit.

[Dvrich89]

@Struggle

sorry what am I supposed to be seeing? 

[Colu]

Your fish have probably developed a secondary infection I would treat  use maracyn  and API general cure ammonia level are still to high API has an ammonia remover filter media bag you could  try 

Edited December 14, 2020 by Colu

[Colu]

It's called API nitra -zorb

[Dvrich89]

@Colu I do have some fluval ammonia remover but my thinking was it would remove the ammonia, starve the bacteria, and crash my cycle. Maybe that’s not the case. 
 

I have been monitoring my ph and today is the first time I’ve noticed a difference in ph. My tanks ph is about 7.0 and my tap (well water) is about 7.8. What does this mean for my fish? 

[Colu]

Sudden changes in pH will stress your fish