Sick rudd

[Rich]

Many of the rudd in my pond are showing signs of fungal infection, by many I mean possibly 100 or more. I'm not sure where to go from here, treating them individually is out of the question and treating them in the pond could be difficult.

Treating them won't get rid of the cause of the problem which is something I need guidance on too.

Does anybody have any advice please?

[Kymba]

Dont know if this site will be of any help to you

Practical Fishkeeping magazine | Treatment Finder

[Lords and Ladies]

Hello Rich.

Have you tested the water at all? Particulary for nitrates, nitrites and ammonia.

[Lords and Ladies]

Also what's your pond like? How big, how old, how long have you had the fish, have they bred, what's the water supply etc.

The more information the better as always

[Rich]

I've looked at all kinds of fish type sites, they all tell me how to deal with one fish at a time.

I haven't tested the water as I only found the problem today.

I dug the pond in 2000 and introduced 9 rudd in 2001, they breed like mad. I don't know if the two mirror carp have been affected.

Here is a photo of the pond in the summer.

[Lords and Ladies]

It may not be much consolation but that's a wonderful looking pond.

I'm at a bit of a loss. Like you say, treating them wouldn't do much good if it doesn't address what the cause of the problem is. Usually fish can resist most of these diseases unless they're under some sort of external stress; like overcrowding, poor water quality, overfeeding..

But your pond is well established, a good size, the fish are breeding naturally etc..

Is there any chance that fertiliser has gotten into the pond? From a lawn, neighbouring farm, somewhere else? The water in your first picture looks a little green. Algae blooms happen of course, but if it's always a cloudy green colour it could be that something is fertilising it.

As for water quality, a nitrite/nitrate/ammonia test would be the first place to start. All aquarist shops sell test kits for these (may be labelled NH3/NH4/ammonia tests), for under £10.

I'm not saying you need to test the water but I'd recommend it if only so you know it's ok. The nitrite/nitrate/ammonia tests usually pick up on overstocking/overfeeding problems but may also indicate if there is fertiliser (or even sewage) getting in there somehow.

Treatment of the whole pond would be very difficult and you'd need to take care with the particular medication you used, as some will kill many things in your pond (including plants) at doses sufficient to have any effect on the fish.

[nightshade]

I had a problem with about a dozen goldfish,I was lucky in getting an
expert for free, the problem was bacterial infection brought to the pond
by gulls excrement and high water temperature
I took them out of the pond(sounds easy )and put them in a series
of brewing bins with air pumps as used in aquariums and treated them as instructed
Suprisingly water temperature can bring on fungal infections so the pond and the fish may need treating

[Chiltern Chris]

Hi,

It looks like Saprolegnia, which is a common fungal infection - it normally looks a little like fuzzy cotton wool on the surface of the fish. This is often seen in the spring before the fish have got their metabolism running at full speed after the winter and so are affected by diseases which don't mind the lower water temperature. Healthy fish should be able to heal themselves as the water warms up but old or infirm fish may die from it. The only way to get rid of it is to treat the fish with an anti-fungal chemical solution in a bucket (which may stress the fish and kill them anyway). So the fish take their chances either way. If it is this, then there's no point treating the whole pond, as it's a common natural disease which would just come back if any fish are feeling poorly.

The other common viral disease at this time of year is carp pox - this looks like a waxy deposit. Again, healthy fish should see this off naturally with only the weak ones succumbing to the disease.

As said above, the pond looks a little cloudy and my be suffering nutrient enrichment which could be from fertilisers, bottom feeding fish such as carp or from previous management e.g. dredging part of the pond over the last year. Maybe worth getting some zooplankton in e.g. waterfleas, Cyclops etc to get munching on the algae.

Cheers, Chris

[Rich]

I hope you're right Chris, doing nothing is something I can cope with.

The water is very difficult to balance, it varies a lot and can be crystal clear for a few months then very cloudy. It has been cloudy for the last two years. I have a small filter but don't want a large one which will clear the water as it's not that sort of pond.

There is also a top pond which has no fish and it is into this that the filtered water is directed, this is where I put daphnia, although I'm not sure it is in big enough quantities to make much of a difference.

I haven't used any ferts in the garden which could have got into the pond.

[Rich]

It got worse this evening. I arrived home from the office to find 15 dead rudd on the surface.