Help! Sick Koi?

[soaresl2]

Hi, hope someone can help me figure out what's up with a couple of Koi I have. I have about half a dozen, all seem fine apart from two (please see pics).

One is a small green Japanase Koi (so I'm told) which I've had about eight months. About a month ago he developed a light grey patch with blackish edges. Doesn't seem to be clearing up. The other is a larger silver Koi which last week developed a pinkish cresent on the top. I've had it for a few years and he's not had it before.

The pond is about a year old, with UV & filter & I replace some of the water regularly; it looks clear anyway. All fish, including these two, are quite lively and seem healthy.

I hear the wrong treatment is worse than none; could someone advise me what might be up and how to treat?
Thanks, ...Leo

[saratogatan]

the 'green' koi is a chagoi, or tea-koi. I am not sure what that patch is. I think it is best that you net it and take a better look, also take a closeup photo. If I were you, I will feel it with my finger, and try apply Hydrogen-peroxide over it and see what happen. There is a good chance the white stuff is sap.

The red mark is on the doitsu is a strong sign of parasite invasion. Net the koi and take a close look. It should be treated the same way you address wound on you leg. I have no experience on treating would on doitsu, I will leave it to others.

stan

[Russell Peters]

The red on the Doitsu Koi is an infection under the large scale. It is best to clean it out and disinfect it. I use a cuetip and mercurachrome. Once you have done that I would use another cuetip and swap some Lamisil under the scale to try to keep out the infection. Keep an eye on it to see if it worsens.

Both the problems with you Koi are a sign of water quality problems.

[saratogatan]

Russ,
Do you know if those scales on doitsu grow back after they are lost ? lokking at the photo, the area below one of those scale is almost completely
infected, it is very likely that the scale get dislodged with wound treatement.

stan

[jnorth]

It's been my experience that the large german scales on doitsu do not grow back at least the ones along the lateral line. Not sure along the dorsal.

Leo, It looks like you have a problem for sure. Can you tell us more about the pond itself? Type/size of filtration? Total gallons of water in pond? The amount of fish? Clear water is not an indication that the water is good so can you give the ph, kh, gh, nitrate, nitrite and ammonia levels? Do you have a microscope? Roughly where do you live as there may be a KHA that lives nearby that can help you out in person. And finally the water temperature.

[JanT]

I would basically agree with Russell. Just do not get the mercurachrome anywhere near the eyes, gills, mouth of your koi. It will kill. Apply with care ONLY to the area in question.
Good advice to find the nearest Koi Health Advisor and ask for assistance. They will have a microscope to find exactly what is causing your problems. Then it can be treated with other medicines if need be.

Best of luck.

[JasPR]

Some more history please. Do you have a skimmer or water flow coming into the pond right at the surface or just below?

[soaresl2]

Hi, many thanks for the feedback . Some further info in case its relevant:

The pond (pics attached) is about a year old, and holds about 3000Lt (800 gallons), max dimensions 2.7m x 2.2m x 0.9m. It has a Hozelock pressurised filter system with UV:
- Bioforce 4500UVC filter rated for 1000 gallons
- Titan 3000 pump rated for 3000 Lt/hr (660 gallons/h)

The filter seems prone to blockage, and if I don't wash out all the sponges in it every week or so the flow reduces to a trickle. The flow from the filter enters the pond an inch or so above the water level.

There about a dozen fish, six koi averaging six inches, and six goldfish averaging four inches. There's not much planting as the Koi seem to eat it all. There are quite a few frogs (plus tadpoles in the basket). So far, I've not tested the water chemical composition as I wouldn't know what to do with the results. I live in Chelmsford, UK; and I don't know of a KHA hereabouts.

The red on the Doitsu Koi does not seem to be getting worse, and the light grey spot on the Chagoi has got a lot smaller in the last few days (though the blackish surround to it is the same size).

I would appreciate your advice on
- does the pond have a parasite problem? Will a testing kit show this or just show chemical composition? Should I add to the water something like Hozelock's anti-parasite treatment?
- should I leave the Chagoi alone as it appears to be recovering?
- is mercurachrome and Lamisil (for the Doitsu) something I can get from a pharmacy? Should I do this as well as or instead a anti-parasite water additive?

Many thanks.

[MikeM]

I'll leave it to others to comment regarding the health of the fish issues. In regard to the health of the pond, it sounds like you need a different filter or need to spend a lot more time on maintenance. Conventional advice is that your filter handle a minimum of half the pond volume every hour, 24/7. I prefer to turnover the pond volume in under an hour. It should never be a trickle. Sponges in a koi pond filter are tough work. I had such a filter nearly 30 years ago (not the brand you mention... I'm not familiar with your brand) and got rid of it after one season. It was simply too much work to keep it clean enough for the water to flow. I do not like the bubbles showing on the surface of the pond. Looks like a high level of dissolved organics, which indicates you may need to do more water changes.... or that the filtration is inadequate to cope despite water changes. In the long run, you need to address the filtration issues to maintain the fish for long lives. ....BTW, you have plenty of fish for the size of the pond. As they grow, you'll find that 3-4 koi and a couple of goldfish is the max even with lots of maintenance effort.

P.S. The lilac is grand. Can't grow those here.

[Russell Peters]

Quote: Originally Posted by saratogatan Russ, Do you know if those scales on doitsu grow back after they are lost ? lokking at the photo, the area below one of those scale is almost completely infected, it is very likely that the scale get dislodged with wound treatement. stan

No, once they are gone that is it.