Do I have micro fish lice and chilo?

[SimonW]

Update:

I checked the koi today and I found:

1) The lesions on the small koi have improved nicely.

What I have done:

Topical treatment with iodine, then back into the same tank. Since then I have also reduced feeding by 30-50% to reduce waste production and thereby to improve the water quality.

Since the lesions are healing, I guess that the water quality is good enough.

2) But an other koi which did not show any lesion under previous inspection now has got a single, localized lesion which looks quite bad. Under microscopy I did not see anything moving. I cannot explain how it got it. So I wonder if any friend here can tell me the cause? Thanks a lot!



3) Furthermore, the tancho gomoro shown in the first 2 pictures has got many red spots on its belly, and the red spots seem to be under the slime coat therefore they are not holes. It does not have excessive slime coat though. It had 2 or 3 red spots already last time, but now there are many more. I also wonder if anyone could tell me what they are. Thanks!

[SimonW]

I wonder if it is possible that these are mechanical damages? I have nothing sharp in the tank, except a submersible pump, an air-stone and a round river stone with a diameter of 10 cm (to cover the water outlet so that no small koi will get sucked and lose scale).

Following picture shows the improvement of a bad lesion on one koi over the last 8 days. That koi also only had one single, localized lesion, similar to the new one:

[RichToyBox]

In going back over the posts, I don't see numbers for ammonia, nitrite, nitrate, pH, KH, temperature. I always like to see what the environment is, as the fish have to live in that water, healed or sick.

The wounds would appear to be caused by parasites. The treatment that you did would not affect flukes, and a microscope viewing should show them, but at 100X, costia which can cause serious harm, would not be visible. It is hard enough to see them at 400X. The PP, if it stayed active long enough, should have taken care of them, but you didn't seem to know if the treatment held or not. I think I would go for the formalin/malachite green treatment, three days in a row with a 25% water change between doses.

[SimonW]

In going back over the posts, I don't see numbers for ammonia, nitrite, nitrate, pH, KH, temperature. I always like to see what the environment is, as the fish have to live in that water, healed or sick.

The wounds would appear to be caused by parasites. The treatment that you did would not affect flukes, and a microscope viewing should show them, but at 100X, costia which can cause serious harm, would not be visible. It is hard enough to see them at 400X. The PP, if it stayed active long enough, should have taken care of them, but you didn't seem to know if the treatment held or not. I think I would go for the formalin/malachite green treatment, three days in a row with a 25% water change between doses.

Thank you Richard!

It makes sense with very small parasites like costia, as my microscope does not have so good resolution.

The water values: 0 ppm ammonia, 0.2-0.8 ppm nitrate (remedied with 0.05-0.1% NaCl), 80-100 ppm nitrate, 5-7 dKH (adding 25-30 gram daily to 600-700 liter), pH not measured continuously, but since I am adding NaHCO3 daily I am sure that pH is stable.

I will treat the tank as you advised!

I forgot to mention that there has not been any flashing or any other abnormal behavior, therefore I have not suspected parasite outbreak. I wonder if it happens often that fish behave normally despite parasite infestation?

[SimonW]

Hello friends:

I have now treated the tank with formalin-malachite green 2 times, and the lesions seem to have improved, but not completely healed.

I did new scrapings, and this time I indeed found moving things, apparently protozoa. Strange that F-MG had not killed them.

The most numerous kind of them are bell-formed and appeared to be anchored on the cells (blue arrows on the pictures which are screen-shot of the videos). Time to time they contract as if they have caught food. I know that there is a kind of protozoa which are not parasites but predators just like these. I seem to see something else moving (red arrow). Is it a chilo? The magnification is 200X.

Video:
https://youtu.be/LQIfi8wVPzM

Screenshot:



Video:
https://youtu.be/4OibKq9LTa8

Screenshot:


Thank you very much for your thoughts on wether these are bad things and why they have not been killed by F-MG! And most importantly, what action I should take as next step.

[SimonW]

I have just found out that this kind of protozoa are called Vorticella.

I guess that they are harmless? Then I wonder how they got onto the fish skin!

By the way, the scraping is from the lesion on the bekko in post #21.