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.