What’s Wrong With This Fish

[bad company]

Just opened up my pond for the spring. This fish has often had white blisters but this looks horrible, it really is a bubble. Anyone know what it is and what I need to do please?

[myvision]

Looks like carp pox.

[bad company]

myvision said:

Looks like carp pox.

Thanks. I just looked that up and carp pox looks likely and probably not dangerous.

[Common Porpoise]

bad company said:

Thanks. I just looked that up and carp pox looks likely and probably not dangerous.

Pox virus itself won't really harm the fish but the waxy lumps can leave lesions which are prone to bacterial infection.
If you see any open wounds then treatment with Vetark Tamodine or Kusuri antibac spray is a good idea.
Is the larger lump behind the head actually solid? it looks almost like a bubble

edit- re read your post! i have to say i have never seen a bubble like that on the skin of a koi.
its likely that its immune system is still basically dormant so its this time of year the fish are most susceptible to disease as all the other bugs wake up first! koi are not really accustomed to the winter temperatures we have in the UK , their natural immunity begins to drop significantly below 16 celsius.
the problem will be if that bubble is ruptured as it will get infected very quickly, and at low temperatures the fish will be very vulnerable too.
i would email pic to London Aquatic Vetinary Services for advice. I'm very familar with pox on Koi but have not seen bubbles like that before. if you would be happy to share your location i can probably put you in touch with a local specialist if outside the south east.
ponds that are more natural in design and with no filtration over winter will also potentially have much higher bacterial count of the nasty aeromonas bacteria that can be a problem for weak fish.

Edited by Common Porpoise on Sunday 28th February 21:41

[bad company]

Common Porpoise said:

Pox virus itself won't really harm the fish but the waxy lumps can leave lesions which are prone to bacterial infection.
If you see any open wounds then treatment with Vetark Tamodine or Kusuri antibac spray is a good idea.
Is the larger lump behind the head actually solid? it looks almost like a bubble

edit- re read your post! i have to say i have never seen a bubble like that on the skin of a koi.
its likely that its immune system is still basically dormant so its this time of year the fish are most susceptible to disease as all the other bugs wake up first! koi are not really accustomed to the winter temperatures we have in the UK , their natural immunity begins to drop significantly below 16 celsius.
the problem will be if that bubble is ruptured as it will get infected very quickly, and at low temperatures the fish will be very vulnerable too.
i would email pic to London Aquatic Vetinary Services for advice. I'm very familar with pox on Koi but have not seen bubbles like that before. if you would be happy to share your location i can probably put you in touch with a local specialist if outside the south east.
ponds that are more natural in design and with no filtration over winter will also potentially have much higher bacterial count of the nasty aeromonas bacteria that can be a problem for weak fish.

Edited by Common Porpoise on Sunday 28th February 21:41

Wow, thanks for that detailed response. I turned off the filtration for winter but it’s been back on for a week now.

I’m based on the North Essex/Suffolk border.

I’m treating the pond with this:-

[tumble dryer]

PH at it's best.

[Common Porpoise]

bad company said:

Wow, thanks for that detailed response. I turned off the filtration for winter but it’s been back on for a week now.

I’m based on the North Essex/Suffolk border.

I’m treating the pond with this:-

I'm afraid to say you are probably wasting your time with the Eradick. It is not really going to do anything to help a fish with viral infection and the active ingredients are likely to cause further stress. The parasites it will target are unlikely to be active yet if your pond is unheated.
That type of general parasite treatment is largely ineffective, especially in ponds with high organic load, as they are p*ss weak to prevent accidental overdosing.
NT labs do a range of more specialist treatments which will be much more effective but only if you know the exact problem you are targeting and if administered at correct temperatures and intervals.

Are the koi flashing or flicking at all? That is usually the first indication of parasite problems.
When treating any pond, medication will have much higher efficacy if organic load can be reduced prior to dosing. ie get the pond and filter as clean as possible before adding.
If your filter has been turned off over winter it is likely that the de nitrifying bacteria that are required for biological filtration of the water (ammonia to nitrite to nitrate) are not yet active so water quality testing is also a good idea. Treatments should Never be added if ammonia and nitrite levels are outside safe parameters.

[bad company]

I cleaned the filter last weekend and again yesterday, it had got surprisingly dirty in the week.

Tested the water today. The ammonia and nitrate levels are fine. The water is very alkaline but it’s always like that.

The fish still has the 2 ‘bubbles’ but seems happy enough. Don’t know what else I can do?

[Common Porpoise]

OK sounds good. Be careful of over cleaning your filter though, especially in colder temps when the bacterial colony is at its weakest. (It's always a good idea to clean media with pond water to prevent chlorine killing off beneficial bacteria) . There are usually two stages to a pond filter, mechanical (solids) and biological (ammonia) so if possible keep the mechanical part as clean as you can, but try to avoid sterilising the biological part.
Alkaline water is actually a good thing when using many treatments as a low KH value can be problematic, especially in warmer water.

If you aren't too far from Ipswich I would recommend a visit or call to Shaun Thurlow of Gipping Valley Koi.
He has been recommended by Lee Burroughs of LB aquatic consultants who is one of the most experienced koi specialists in the UK... Unfortunately now retired.

[bad company]

Common Porpoise said:

OK sounds good. Be careful of over cleaning your filter though, especially in colder temps when the bacterial colony is at its weakest. (It's always a good idea to clean media with pond water to prevent chlorine killing off beneficial bacteria) . There are usually two stages to a pond filter, mechanical (solids) and biological (ammonia) so if possible keep the mechanical part as clean as you can, but try to avoid sterilising the biological part.
Alkaline water is actually a good thing when using many treatments as a low KH value can be problematic, especially in warmer water.

If you aren't too far from Ipswich I would recommend a visit or call to Shaun Thurlow of Gipping Valley Koi.
He has been recommended by Lee Burroughs of LB aquatic consultants who is one of the most experienced koi specialists in the UK... Unfortunately now retired.

Thanks again.

That fish is over 20 years old, we’ve got rather attached to him.

[Boosted LS1]

Boosted LS1 said:

I'm not an expert but am a great believer in keeping chemicals out of the pond except if you see a bacterial infection. Not sure why you turned off the filtration but anyway if that was my fish I'd keep it under observation and do everything to maintain healthy water without additives. Certainly make sure you have a decent UV working. The fish may improve as the weather warms.

[bad company]

Boosted LS1 said:

Boosted LS1 said:

I'm not an expert but am a great believer in keeping chemicals out of the pond except if you see a bacterial infection. Not sure why you turned off the filtration but anyway if that was my fish I'd keep it under observation and do everything to maintain healthy water without additives. Certainly make sure you have a decent UV working. The fish may improve as the weather warms.

Why do I need the UV working? I thought that was just there to keep the water looking clear by killing algae.

[Boosted LS1]

It kills everything, ie parasites, bacteria etc that flow past it.

[Common Porpoise]

Boosted LS1 said:

It kills everything, ie parasites, bacteria etc that flow past it.

not so much..
UVCs (clarifiers) are largely just to flocculate algae cells. you would need a much more intense UV steriliser to have any significant impact on pathogens.

[Boosted LS1]

^ Is a UV steraliser different to a clarifier? I've not heard of a UV clarifier but they may be one and the same. From a quick search.

"A UV steriliser is used to combat and kill harmful waterborne bacteria, viruses, fungi and small protozoans".

My ponds very basic, I have the UV lamp and I clean my filters twice a year which is usually when I notice they're getting blocked. I only clean the gauze stuff, never the bacterial parts.