Here we look at other ailments you may come across that don't fall into the catagories we have already looked at (bacterial, viral, fungal and parasites)

Tumours – Most fish tumours develop directly under a fish’s skin and are benign. They are rarely a hindrance and the fish can usually live a normal life. Very rarely a fish will suffer with malignant tumours, which require specialised veterinary treatment.Constipation – A diet lacking in fibre is the common cause of constipation. Constipated fish can typically be identified due to bloating of the abdomen and the presence of long, stringy faeces. If untreated, this can lead to other ailments.The simple remedy is to feed the fish boiled, skinned tinned peas for 2-3 days instead of the regular feed. Constipation can be avoided by giving the fish a well-balanced, varied diet.Temperature Related Symptoms – During cooler seasons the fish move to the lower depths of the pond, stop eating and become very lethargic. This behaviour is commonly misinterpreted by novice fish keepers as an indication of illness. If the water temperature is below 5°C these actions are normal and require no treatment, unless other symptoms are present.Mating Behaviour – Another cause of behavioural change (and in some cases physical change) in fish can be due to spawning. Mature fish will be induced into spawning by temperature fluctuations in the water, usually early morning in mid spring, and sometimes around early to mid autumn.During mating the male fish will chase the females, which can sometimes seem fairly aggressive. Male carp and goldfish develop tubercles around the gill cover and along the front of the pectoral fins. The tubercles are sometimes mistaken for white spot, but are actually small barbs, and are only present on the pectoral’s leading ray and the operculum.

Physical Injuries – Pond fish can sustain injuries if they attempt to leap from the pond, if the pond contains sharp décor, as a result of been mishandled, or if they have been attacked by a predator. As well as the physical injury, the fish will probably suffer with an amount of stress and will usually display a behavioural change; become lethargic, lose appetite, etc.Rather than deal with the injury, the best course of action is to remove the cause of injury; netting the pond to stop leaping, removing potentially dangerous objects from the pond, installing a predator deterrent, etc. In a well kept, healthy pond the fish should soon heal and regain its regular behaviour.Lack of Oxygen – A pond suffering with a lack of oxygen will be apparent as the entire fish community will gasp at the surface of the water, usually under waterfalls, filter outlets or fountains.

Oxygen diffuses into the pond through the water’s surface and is added by plants as they photosynthesise during the day.Colder water can hold more oxygen than warmer water.Oxygen is used up by fish and bacteria. Plants also absorb oxygen through the night.On a hot summer night, when the water is warm, the plants, fish and bacteria have high metabolic rates and are using the pond’s oxygen quickly. The pond can soon become starved of oxygen and the fish can begin to suffocate. A pond’s entire stock can be lost in a night due to a lack of oxygen.It is vital, especially during the summer, that waterfalls and fountains are left to run through the night, their movement will increase the pond’s surface area and inject oxygen into the pond. Air pumps can also be added to bubble air through the water.Some fish and pond treatments can also reduce the amount of dissolved oxygen in the pond water. It is important only to use necessary treatments at correct dosage rates to reduce the chances of suffocating a pond and stressing the fish.