When we get drenched in the rain on our way to school or the office, it is most likely that we will catch a cold the following day. Almost all of us were taught in our childhood to dry our hair and body properly after taking a shower so that we do not catch a cold.
If you think hard about it, there is a question you cannot ignore. Fish live in the water throughout their whole life. So is it possible for fish to catch a cold? Is there an optimum temperature for fish where they can lead the healthiest life?
We all know that many animals hibernate during winter. So when it comes to fish, do they hibernate too? We have all seen water bodies being frozen in the arctic and antarctic region, but have never asked about what happens to the fishes that live there.
These are some of the most simple but commonly overlooked questions. But not anymore as we take a dive into the waters and find the answers to them.
Fishes and the optimum temperature for them
Temperature is an essential element for every living being and fishes are no exception. Fish are cold-blooded animals which means they cannot regulate their body temperature at their will. Rather they have to depend on the temperature of their surrounding environment to regulate their metabolism and physiological activities.
The optimum temperature for a fish varies from species to species. For example, a tropical fish thrives on the temperature between 75°F to 80°F (23.89° to 26.67° C). But a cold water species prefers a temperature below 70°F.
If the water is too cold, the metabolism and immune system of fish gradually decline over time. This makes the fish less active and more prone to being affected by diseases.
If the water is too warm, the metabolism of fish increases and so does the breathing rate. With a faster breathing rate, a shortage of oxygen is created which makes the fish more susceptible to diseases.
So in the wild, fishes usually change locations or simply adapt to the temperature as the rise or fall of temperature in a water body is a lengthy process. But nevertheless, it is very important for fish to reside in an environment with their respective optimum temperature.
Does a fish catch cold like we do?
If we start defining what actually is “catching a cold” and its pathogenic background, then it might turn into a complex microbiological discussion. But if we are to answer it with a simple yes or no, then yes.
Fishes do catch a cold. As we have mentioned, fishes have an optimum temperature depending on their species. When they are forced to reside in an unsuited temperature, they become more susceptible to various viruses, bacteria, and other pathogenic microbes. And by getting affected by such microorganisms, a fish may catch what we call a cold.
We have to keep in mind that the cold caught by fish does not show symptoms as we humans do. There is a pathogenic difference between the two kinds of cold. Fishes do not cough or sneeze like us. Rather they show respiratory illness and infection, slight inflammation, elevated temperatures, etc.
Similar to us, the cold caught by fish is also contagious. So if you own a hatchery and find out that one or some of the fishes have caught a cold, it is best to separate it or them from the other healthy ones. Though there are treatments for such diseases, it does not fully cure them. So the best course of action is to take precautions and avoid catching a cold altogether.
Fish Survival in Winter
Whenever we touch the water in the cold winter, a shivering sensation is sent throughout our whole body. It can easily make us wonder about how aquatic animals survive in this cold water. As we have mentioned earlier, fishes are cold-blooded animals, unlike mammals. So it is not possible for them to regulate their body temperature according to the environment.
Low temperature can cause much harm to fish by making them more prone to diseases and even killing them in the most extreme cases. So it is very important for a fish to survive in the cold waters during winter.
During the cold days of winter, fishes usually slow down their metabolism, resulting in lesser growth and limited movement in order to conserve energy. On the other hand, some fishes start migrating as they notice the decrease in water temperature and reach a location that offers a warmer environment. And as winter goes away, these migratory fishes come back to the locations of their natural habitation.
Some fishes have adapted to the cold weather over the course of time and some others show a process similar to hibernation. And by choosing the best method, fishes survive through the cold fangs of winter.
Fish Survival in Cold Arctic Water
Speaking of cold water, there is almost no worthy competitor that can beat the Arctic water. The average temperature of Arctic water is 28.6°F almost throughout the year whereas the freezing point of fish blood is approximately 30.4°F. So it is only natural to assume that fishes must freeze in this water.
But the scenario is quite different. The fishes living in the Arctic and Antarctic region have developed a special protein in their bloodstream known as antifreeze. This protein prevents the formation of ice at the cellular level to prevent cell death. It also helps the blood to flow naturally without freezing due to the extremely cold environment of Arctic waters.
On the other hand, in frozen lakes and ponds, ice covers the surface area due to its comparatively lower density. As ice is a poor conductor of heat, the water beneath the frozen surface stays relatively warmer than that of the surface. With the help of antifreeze protein and ice preventing heat conduction, fishes carry out their lives in the arctic waters.
Fishes and hibernations
One might expect that fishes hibernate like many other cold-blooded animals. This assumption is correct to some extent. During winter, fishes enter a dormant state where they lower their metabolic rate as much as possible. By doing so, they heavily restrict their movement, growth, and other physiological activities.
As a result, they require a very little amount of food and oxygen to survive in the winter. Oftentimes, ice layers form outside a fish’s body. This layer of ice prevents heat from reaching the body of the fish and keeps it warm.
While this resting state sounds very similar to hibernation, we must keep in mind that it is actually not hibernation. This process is known as “Torpor”. Next time you hear about fish hibernating, you can rest assured that they are talking about the Torpor state.
Conclusion
In the natural hierarchy of living beings, fishes are significantly more developed than the majority of the animals. Due to this elevated position in the natural hierarchy, fishes can catch cold like us humans though the fundamentals of catching a cold are different between the two species.
Like many other living beings, fishes also have a required optimum temperature without which it becomes difficult for them to survive. But over the course of time, these fishes have adapted survival methods against the perils of nature.