Fish Diseases

Fish disease is a fact of life and in common with all pet owners, pond fish keepers need to be able to recognize the signs of ill-health, the first signs of any problems are usually the pond fish acting oddly this can be many things from refusing to take food when offered to the pond fish flashing on the pond floor, clamped fins, heavy respiration, self-isolation, gasping at the surface or water return, jumping – all which indicate the need for further investigation and may signal there is a problem in your pond.It is important that you act fast in diagnosing and treating your pond fish in any of these cases, quick diagnoses can mean the difference between life and death for your pond life.Fish disease can be both highly distressing and costly not only the treatments but also the pond fish replacement costs. A key aim is to encourage prevention via regular water testing and husbandry of your fish pond. This is particularly important with koi ponds as their often-high stocking levels and reliance on biological filtration for good water quality. In general diseases are often oversimplified, which in turn leads to misunderstandings about diagnosis and treatments.I personally have always believed that there are two key ‘musts’ that have to be carried out regularly in order to ensure that your pond fish stay healthy.1- Regular water checks, you can buy a test kit from your local pet store for as little as £15 A small price to pay for the peace of mind of knowing your pond water is in A1 condition, this is one of the single most important factors when it comes to fish keeping, think of your hobby as not so much keeping pond fish but ‘keeping water’.2- Watch your pond fish closely, learn there behaviour, there personality (yes even pond fish have one) and there movements, it will be much easier for you to notice and changes in your pond fish behaviours which could result in an all important early diagnosis.I have put together and explained a few of the most common diseases you are most likely to encounter as a fish keeper, I must stress that you should not use these guides as a means of diagnoses and treatment, bare in mind that many fish diseases have very similar symptoms professional help should be sought at the first signs of any problems on your pond fishes health.

Whitespot

The parasite Ichthyophthirius, or as its more commonly known white spot or Ich, is a very common fish disease which most fish keepers will have to deal with at sometime, it is capable of affecting virtually all fish species and spreads extremely quickly. Ich has a complex life cycle that and that has a major bearing on treatment methods. The parasite constantly moves under the pond fishes skin, feeding on destroyed cells and body fluids. The parasite feeds on the fish body cells until mature and then 'punches' its way out of the skin. It then attaches itself to a plant or some other object in the pond and forms a capsules around itself. Inside the capsule, the parasite, repeatedly splits, producing up to 1000 other parasites that eventually 'hatch' from the capsule and swim to find a fish host which is the reason it spreads so quickly. These small parasites are the infective agent. They burrow into the pond fish's skin and the cycle starts all over again.

Recognising Whitespot?

The first signs of white spot will be the fish behaving oddly the fish may show signs of irritation, flashing, weakness, loss of appetite, and decreased activityEventually the pond fish will show white spots or ulcers on its skin or gills, White spots on the fish however should not be used as the only means of diagnosis because other fish diseases may have a similar appearance, you should seek urgent professional advice, many larger koi outlets provide a free scale scrape for sick pond fish, they will then put the sample on a slide and view it under a microscope, giving you a accurate diagnosis.

Treatment

Only when the parasite is in its free-swimming stage can it be sussesfully treated So treating white spot in your pond fish can be quite complicated, the treatment for the dieses must be carried out for quite a prolonged period of time in order to kill the parasite as it exit’s the fish. The length of time that you have to treat infected fish greatly depends on the water temperature At 7oC the life cycle will take six weeks, whereas at 25oC it will be complete in a week. I personally have never used the ‘off the shelf’treatments instead I would recommend you visit a koi dealer that is licenced to sell stronger treatments such as formalin, or potassium permanganate

Fin Rot

Usually a sign that water conditions in your pond are far from perfect, Fin rot is caused by various parasitic bacteria and causes the fine flesh membrane between the rays of a fish fin to become opaque and start to rot away leaving just the bare fin rays which in turn start to rot.

Recognising Fin Rot

The fins begin to fray and get ragged, becoming shorter over time. Usually the edges look white, and the pond fish may even develop a Cotton Wool like growth. As the disease advances the area may become red an inflamed, with bloody patches appearing as more of the fin is eaten away.If the infection spreads to the body of the fish it will probably die. All fish in the affected pond will need to be checked and water quality needs improving.

Treatment

The problem can be treated if caught quickly with a antibacterial pond treatment. Recovery will take sometime even up to 8 months in some cases. Successful treatment will see transparent tissue growth between the pond fish's fin rays.In severe cases antibiotics may need to be injected into the pond fish this can only be done by a qualified vet of professional expert in fish health.

Anchor worm (lernaea)

This is one of the most common parasites that you are likely to encounter in fish keeping, it attaches itself to the fish burying its head inside, its body and tail are usually visible, if left untreated secondary infections can arise at the point of entry on the fish, the parasite can also, in the correct conditions lay eggs in pond which will spread to other fish in your pond.

Recognising Ancor worm
The parasite is clearly visible to the naked eye, usually around 10 to 12 mm in length clinging to your pond fish usually around it’s tail or dorsal fin.

Treatment
I would strongly recommend you seek professional help here as manual removal is required usually with tweezers. If you do attempt to remove the anchor worm from the pond fish yourself, ensure you remove the whole of the parasite this is very important, dab the worm with potassium permanganate before attempting to remove, it will immediately release its grip on the fish.

The gill and skin fluke (dactylogyrus)
Flukes are another parasite that you are likely to encounter in pond fish keeping, this is a family of the monogenetic trematode genera, characterised by its large grappling hooks which they use to attach itself to the fish, Gill and skin flukes can cause lesions and tissue damage creating entry sites for secondary infections.

Recognising gill and skin flukes
Unless you take a scrape from the pond fish and view it on a microscope you can’t see the parasite, it is not uncommon for fish to have a few gill flukes attached to it, it is only in large numbers that the parasite becomes a problem. The fish will show the usuall classic signs of irritation flashing jumping, and rubbing against objects in the pond.

Treatment
Ridding your fish pond of flukes altogether is virtually impossible as they are increadably resilient to treatment, however if you see that the fish in your pond are obviously distressed and you are sure that it is from fluke infestation you can try one of two methods firstly a salt (use non-iodised salt available from your aquatic dealer) twice over 2-3 days, secondly a treatment of Malachite or formalin again this is available from all reputable koi abd pond fish outlets.