You may not be an expert on fish behaviour or health but you know that your fish can get sick. Unfortunately, in many cases fish die before their owners realize that they’re ill but there are signs that you should watch for if you suspect your fish might be ill. In most cases, when a fish develops a disease, its behaviour or appearance will change noticeably. A vigilant fish owner will recognize these changes and take the necessary steps to get their fish healthy again.
So the first thing a pet owner needs to do is observe their fish when it’s healthy. If you don’t know how your healthy fish behaves or looks it will be extremely difficult to recognize behaviours that indicate your fish is sick. Most fish sickness is the result of stress; even in humans stress compromises the immune system and in fish this is often fatal. Some of the most stressful and therefore most detrimental health factors for fish include poor water quality, wildly fluctuating water temperature, insufficient space in the tank for fish, lack of oxygen, or poor nutrition.
If you suspect your fish is ill, there are some clear signs of a problem. First of all, changes in eating behaviour often indicate illness as do changes in exploratory behaviour. If your fish refuses to eat or swim around the tank, these could be early signs of illness. Even when an inactive fish become suddenly active you might be dealing with an illness. Visible spots or lesions on your fish’s scales also indicate illness. Finally, changes in swimming patterns can indicate sickness; so, if your fish is floating, sinking, whirling, or swimming sideways, you may have a problem.
Because fish cannot vocalize illness in the way that humans or other mammals do, it is extremely important to watch their behaviour to discover illness. If you notice any of the symptoms listed above, visit a vet immediately.