How to Tell If Your Fish Is Dying?

Carol M.
Fisheries Consultant

You may not want to be in the situation of losing your beautiful creatures. For all the sacrifices you have made taking care of them, purchasing equipment without forgetting the joy their presence gives you. Losing that quality moment you spend with them it’s devastating.

But how can you prevent such an ordeal? To be sincere, the situation is reversible, though it depends on the attack level. If you counter the situation early, you can revive your fish. However, there is no harm in learning some of the signs of a dying fish, in case you experience it, you will be on the safe side.

Some of the indicators to look for in a dying fish include;

  1. Cloudy Pupils

When you notice fish with cloudy pupils this is a symptom of a fatal illness like fin rot or pop eye disease. It's best if this disease is contained otherwise your pet will die soon. Again, some of these infections are contagious and this can affect other fish in the aquarium.

Again, the popeyed disease is potentially fatal and can affect both eyes. Therefore, immediate medication is necessary. You should quarantine the sick fish and treat them accordingly.

  1. Lack of Appetite

If your fish fails to eat, it's a sign it has an infection. Prolonged loss appetite makes your fish emaciated and immunity lowers. Your pets contract diseases which easily kill it due to low immunity. So, if you feed your fish and you notice they show no interest and even after sometime you find the food floating this is an issue for concern.

  1. Color Fading

Are your fish having dull colors? This issue may be riskier than you think. Most pet fish are colorful, especially the fins. Their color combinations especially for different species forms a rainbow aquarium. So, if you wake up one day and notice color fading in your guppy, betta, goldfish or other species, this is a cause of worry.

You may also notice white or fuzzy growths on their bodies, which mostly result from bacteria or fungal infection. On the fins, they can get streaks especially due to poor water quality with high ammonia levels. You seek immediate help for your fish or else they will die.

  1. Gasping for Air

This condition can result due to several factors, for instance, illness,  poor water quality parameters or a blockage in the respiratory system. If you encounter this issue, you should change the water immediately to enhance breathing. Improve aeration and provide the appropriate medication for the illness.

  1. Sudden Weight Loss and Muscle Atrophy

Loss of appetite leads to sudden weight loss and your fish becomes emaciated. Again, some infections will lead to weight loss depending on the level of attack. Muscle atrophy in fish means the wasting or loss of fish muscles. This condition may occur as a result of aging, starvation( if fish fails to eat) or even diseases.

How do you know your fish is suffering from muscle atrophy? You may notice some signs like;

  • weakness in their fins
  • trouble swimming and balancing
  • Difficulty in eating and swallowing

If left untreated, these conditions make the fish weaker until they are left with no energy.

  1. Gills Flap and Change Color

A key sign of death is when the gills flap or even the operculum stops moving. Gills are an essential organ as they keep the fish alive. They facilitate the air exchange between the fish and their environment by taking in oxygen and expiring carbon dioxide from the system. If you notice this symptom the fish is probably dead and if not nothing much can be done.

Also, the gills may turn brown, which is a sign of nitrite poisoning or red patches due to ammonia build up. Nitrite is more lethal than ammonia and thus you should rapidly change the water and test until its zero. The gills can also appear blotchy if their tissues are dying from a fungal or bacterial infection. Therefore, be keen to note your fish’s gills appearance and if any abnormal discoloration, intercede accordingly.

  1. High Breathing Rate

When your creatures are under stress from diseases or parasites or poor water quality, they experience rapid breathing. The fish respond by producing excess mucus which covers the body including the gills and thus they struggle to breath. You need to assess this situation to determine what's causing the rapid breathing and address it.

  1. Confusion and Unusual Behavior

A normal healthy fish will be active and will occasionally rest when tired. But if you find your fish darting from one side of the tank, or its immobile staying on one spot, then all isn't well. Secondly, if the fish displays erratic swimming , something should click in your mind. Swimming sideways or showing confusion is a warning of deteriorating health.

  1. Swollen Belly

Fish having distended belly or bloat may be experiencing dropsy. If a swollen belly turns out to be dropsy, then the odds of death are high. This illness mainly results from poor water quality and results in a distended belly.

Dropsy is a symptom of so many issues that triggers fluid accumulation, especially in the abdominal region. To differentiate the condition and bloating, your fish will have a pinecone appearance if you observe it from the top.

The fish becomes inactive, stops feeding and less swimming. With time the condition becomes progressive and has other symptoms like anemia, gill discoloration. Other symptoms are bristle scales, swollen anus, puffy eyes and fibrous feces.


There are so many symptoms of a dying fish as explained above. For your fish to express these signs, it means the water conditions are unfavorable, poor diet or there are infections and parasites. To save your fish from uncompromised health, ensure you take good care of them. Be keen to observe the aquarium creatures ensuring there are no environmental factors triggering health complications. Also, when infected address the condition immediately to save their lives.

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