Friday, June 09, 2006

First aid for fish. Dying pond fish, illness symptoms bloated/floating/ulcers.

A couple of weeks ago I had a problem with some fish in my pond. Two of my sarasa comets were showing signs of distress. One had a red blotch developing on its side, and another was having trouble with its bouyancy, and seemed very lethargic. Although she was able to swim and move around the pond, when she stopped she would slowly float up to the surface, and go upside down. Also she looked very bloated.

I know of two very helpful websites which I immediately visited to learn what the problem was.

These are and Both sites provide excellent advice on how to diagnose illness and disease your fish may have, and what to do about it.

I have learnt a lot about the problems my fish were having, and why too. The quality of my pond water is normally very good - clear and clean, with virtually zero nitrates levels, and perfect pH balance (acidity/alkaline). Also we have quite a few baby fish hatched, so this in itself indicates that the balance of the pond is comfortable for the fish to do what comes naturally! Some tests to check the water-quality proved everything was ok and within normal ranges, so this was not the cause for my ill fish. After reading up on the FishDoc and PondDoc sites this is what I found out:

Your fish are most vulnerable to parasites and disease at the start of the year, when the temperatures are not stable and high enough for your fishes immune systems to "get going". This year in particular the UK has had a slow start to the spring/summer season, with temperatures fluctuating wildly. Bright sunny, almost summer days early on, but then dropping back to almost freezing again a day or two later. This means the water temperature in the pond has been sufficient for the lower life forms to come out of hibernation (e.g. bacteria and parasites), but it has not been a consistently high enough temperature for the fish to develop their own immune systems properly.

The result is that tiny critters have been able to cause problems before the fish are strong enough to defend themselves. Particularly since the fish have been staying low at the bottom of the pond during the winter where parasites can attach themselves to a fish, and wait until warmer days when they begin doing their damage!

One of the things both FishDoc and PondDoc recommend is that you do not jump to conclusions when diagnosing your fishes illness. It is far better to be sure about the kind of disease before attempting to provide a cure.

In the meantime they recommend that you take some initial "first aid" measures to help start your fish on the road to recovery. A salt bath is a good initial treatment for fish. It helps to kill external bacteria and parasites, and helps increase the natural mucous film coating on your fish. It is better to use something like Interpet Pond Guardian Salt which is designed for use in ponds, but you can use either sea-salt or table salt instead. Do not use salt containing anti-caking agents such as sodium ferrocyanide (yellow prussiate of soda – this can release hydrogen cyanide when exposed to sunlight).

If you have never done a salt bath before here are some tips:-
  • The amount of salt you use in a container or holding tank does look like a lot of salt! It has to be sufficient concentration to make it effective for a short term bath of maybe 20 minutes. The page at the link above explains why you need this much, and diagrams show how the salt bath works on your fish.
  • Use a white container to put the fish in for its salt bath (I use a 10 litre empty fish food tub, but this may not be large enough if you have bigger fish). This will help to "light up" the fish and make it easier to inspect the general condition of its body, scales, etc while it is having the bath. Have the container filled, ready and by the pond so you can transfer the fish quickly and easily.
  • Have a decent size net with a good long handle. Use it with slow and gentle movements to catch the ill fish. Once caught, lower the whole net into the container and down and away from the fish, rather than just tipping the fish into the container because you run the risk of the fish struggling and falling onto the edge of the container.
  • The fish may float in the bath. This is to be expected, and occurs because of the concentration of the salt making it more bouyant (think how it is easier for you to float in the sea in comparison to when in a swimming pool).
  • After this high concentration salt bath (do not leave the fish in it too long, generally 15-20 minutes, and certainly no more than 30 minutes, depending on the strength of the fish), you should consider adding some salt as a general tonic to the main pond. This will help all your fish build up their natural slime defence on their bodies, and help to weaken parasites.
  • Follow the instructions carefully for any other disease treatment that may need to be added to the pond once you diagnose what the problem is. Often parasite and disease treatments contain formaldehyde so you must not overdose the pond.
  • If you add salt to the pond, more than say 1% solution, you should consider that some species of plants cannot tolerate salt and may be best removed from the pond and put into another container for a couple of weeks.
  • After 1 or 2 weeks, perform some water change topups in the pond to weaken the salt solution. This will probably occur naturally with regular topups and rainfall.
My two fish turned out to have different problems; one had an ulcer on his side under a scale, which had swollen up and become infected; the second fish had a systemic bacterial infection (meaning the bacteria have infected the internal systems of the fish), called "dropsy". This is when the fishes kidneys are overcome by a bacterial infection, and are failing to remove excess water/fluids from the fish inside, and this causes its body to swell and become bloated, and as this becomes worse it affects other organs such as the swim bladder, and makes their eyes bulge out (known as "pop-eye"). Unfortunately by the time this kind of infection makes itself apparent in this way, it is usually too late and too far gone for the fish to recover.

I used some Interpet Anti Ulcer which acts against systemic bacterial infections, but as I feared, it was too late to have any effect, and I had to put my fish down. This article probably covers using the clove oil/vodka method is most detail: What is the Most Humane Way to Euthanize a Fish by Of course this should be a last course of action after you are certain there is nothing else that can be done for the fish.

Thankfully the other sarasa comet who had the ulcer is now looking much healthier. The redness on his side has gone, and the puffed up scale is going back to normal.

This is the first time I have had to be doctor to my fish. Perhaps if I had been more aware of some of the common fish disease symptoms and cures beforehand I might have noticed and been able to save my other fish. I can only recommend that you too read up some of the pages in these two excellent web sites. Perhaps you should consider adding some salt to your pond at the start of the season as a general tonic to help your fish build up their immune systems. At least have some salt available for any emergencies, and consider having some of the more common parasitic and bacterial cures on hand too.


At 20/3/08 4:46 pm, Anonymous Anonymous said...

some very good tips !!
i think you saved a fish today
thank you !!!

At 21/4/08 10:21 pm, Blogger Jim Prior said...

hey, I'm pleased about that, great news!

At 11/4/09 5:42 am, Anonymous Anonymous said...

Thankyou for the tips. We have lost one fish in our pond yesterday and am now trying to save another in a seperate tub. It is so strange that you say add salt because last night we put a few drops of Nikken pi mag water (salt based) drops in and he seemed to perk up. We thought as it was the smaller fish that the food was too big and given too early. He is still floating and then diving deep in the tub so we will try the 20 minute salt bath. Many thanks for this advise
Ann & Jo

At 13/4/09 9:18 pm, Blogger Jim Prior said...

You're welcome. I do hope your fish recovers.

At 20/6/09 11:32 am, Anonymous Anonymous said...

hi there,my pond changes color very quickly from very clear to very green in the space of a few hours of glorius sunshine, i lost a gold fish yesterday im wondering if the green is the problem last year it got like porridge and had to have an emergency water change, i have lilys in there, uv/3 stage filter from a pump which then goes back down a waterfall, somedays they seem happy but most the time they mope i have had 4 casualties now 2 gold 2 shubunkins and im worried for my ghost and my koi.

At 22/6/09 8:14 pm, Blogger Jim Prior said...

Hi, the reason why it changes colour is because your pond has masses of phytoplankton suspended in the water.

Phytoplankton is like a plant (it is a form of algae), which photosynthesizes just like any other plant. When sunlight falls on them the energy from the sun causes them to absorb carbon dioxide, give out oxygen and produce chlorophyl which causes the green colour.

Normally they are so tiny that you don't see them, but when there are millions of them together they cause the green colour to appear, and your fish to disappear hidden by the pea soup colour!

Usually fish are not bothered by this, but at night in the absence of sunlight the process reverses and the phytoplankton uses up the oxygen and gives out carbon dioxide. If there is too much of this it can end up suffocating your fish, and they will appear at the surface looking distressed gulping for fresh air when you are not around (no - not food!).

The immediate thing to do is get more oxygen into the water so your fish can breathe ok. This can be a fountain or a good venturi, or airstones.

Next protect your pond from strong sunlight. Offer it some shade. Is the water too shallow? If so the sun will heat it up more quickly and warm water causes less retention of oxygen in the water, and more breathing problems for your fish.

Do you have a nice big, umbrella, or a large broad leafed plant in a pot that you can position to cast some shade?

You have a UV, but have you changed the bulb recently, or is the UVC not strong enough rating? The UV clarifier is supposed to combat green water, but it might not be strong enough for your quantity of water, or perhaps you're running the water too fast through your filter and UVC. The water must pass slowly enough for the UVC to kill the phytoplankton, and the good bacteria in the filter to deal with the fish waste in the water.

Are you over feeding your fish? Too much food means too much ammonia (fish pee), or uneaten food in the bottom rotting. The bacteria in the filter convert ammonia to nitrates (fertiliser) and if there are not enough big plants (marginals, lilies, etc), to use up the fertiliser, who else is going to use it?

You got it - the phytoplankton!! And they eat and grow and multiply, to thousands, then millions, then billions.

Just add sunlight.
Bang - Green water.

At 25/9/12 3:29 pm, Anonymous Anonymous said...

OK!, I started a Pond about 4 months ago, 5' 8" x 4' 8" x 12" deep, about 125 Gallons.
I got a pump with a Fountain and I made my own Filter going on to a small Waterfall, I got lots of Pond plants and covered the bottom in washed rough sand.
I left it for a while and then got 25 Koi Carp, within a week, 15 of them died, I got Medifin and put that in, seemed ok then the water turned green, I got a Algi killer and it turned the water brown, I changed half the water with tap water, did a Ph check and was 7.5, then the water turned green again and more fish started dying, I got 10 more fish and treated with medifin again, seemed ok for a while but they are showing symptoms of illness again, swiming erratically and floating to the top and staying in one corner, could you advise what to do next, I never knew it would be so hard to keep fish.

At 26/9/12 9:35 pm, Blogger Jim Prior said...

Hmm, sounds like you've got too many koi fish for such a small (shallow) pond. I'm guessing they're quite small now, but they will (would) have grown fairly large, and your pond just wouldn't have the capacity to cope with them. Koi are greedy eaters, and excrete far more ammonia than humble goldfish do. If you don't have enough water volume for the number of fish and a proper filtration system for koi, the ammonia can build rapidly. With such a shallow pond, sunlight will heat the water quickly, and this can reduce the ability of the water to hold oxygen properly. Your fish will suffocate. If the fish appear to be gasping for air at the surface this could be a clue as to what is going wrong. If your filtration is not large enough to cope with the amount of ammonia, your fish will literally be swimming in sewage and will suffer. Ideally your pond should be much deeper, about 3 feet at least. This extra depth helps prevent wild temperature changes in summer, and gives protection from freezing in winter. Shallow water will quickly green up in strong sunlight, and is a strong indication that the water may be getting too warm, and that the phytoplankton (green algae) are having a wonderful feast using up the nitrates converted from the ammonia by the bacteria in the filter. If you are feeding your fish too much this will also add to the amount of ammonia the fish excrete, so reduce the amount you feed them. Consider adding a venturi to mix more air into the water, in case they are suffocating. Is the corner where they go to where the fountain/waterfall is? Because thats where the most oxygen will be. Consider providing shade to keep the bright sunlight off the pond, so the water stays cooler. Best of all dig the pond deeper - seriously! You're wasting a lot of money on expensive fish. Better to start off with small common fish which place less demands on the ponds ability to support life, particularly with a new pond that is still getting established, and learn like this rather than keep killing expensive koi. Hope this gives you some ideas. Best of luck.

At 27/9/12 1:47 pm, Anonymous Anonymous said...

Thanks Jim
The Pond is in the shade of trees and hardly gets any Sunlight, so I don't undrestand why the Algi?
I should have read up on building and keeping a Koi Pond before I started.
OK! I will have to think about digging it deeper but where to put my fish while I do this..Mmmm.
I will have a think on this.
At the moment I am replacing the Pond water with tap water to keep them going untill I think of something...

Thanks again

At 2/10/12 1:18 pm, Anonymous Anonymous said...

Hi again Jim

Just a thought.... Could Frogs be poluting the water? there are lots of large frogs at night in the Pond.


At 3/10/12 5:04 pm, Blogger Jim Prior said...

When I built our new bigger pond, we put our fish in a temporary paddling/swimming pool in the garage. One with PVC sides, and vertical metal poles supporting its sides. It cost about 60 quid from an Ebay vendor. I also had a bio-filter set up to circulate and clean the water in the pool. The fish were in that for about 9 months until the new pond was ready.

While tap water is ok for topping up and making partial water changes, its not a good idea to do it too regularly. You should add something like Fresh Start in to remove any chlorides, metals, etc and soften the water. Otherwise the chlorine in the water kills the good bacteria that you should be trying to establish.

I doubt very much that frogs are a problem. If anything they are usually a sign of good water quality.

Hope it goes well.


Post a Comment

<< Back to Jim's Pond Blog Home