Fish has a streamlined body shape that enables it to swim across waters moving from one place to another. Basically the shape has to be long and sharp enough to enable it to overcome resistance of the water so that they will have higher chances of survival. Tropical wild fish found in rivers, streams and lakes all have the basic shape that enables them survive in the wild and escape predatory creature with the exception of certain fish species kept in home aquarium which has a rounder appearance just like the goldfish which is a coldwater species.
The reason why the body shape of home aquarium species is highly different compared to those in the wild is because of selective breeding to mate the choice of fish with certain attributes to produce offspring with desired characteristic. Because of these, fish that were rounder and created specially for home aesthetic appearance usually lacks the survival ability of a native tropical fish in the wild. In fact, I should mention here also that besides the long and torpedo shape of a common fish, there is also another fish variety call the discus (an Amazon River native) which looks flat and round and it is also an extremely fast swimming species that cuts through water with ease.
Skin and Scales
Body of every tropical fish is covered with scales, which acts like a protective armor. It can be easily lost caused by rough handling but that would not pose any problem to the fish because in time, it will regenerate back. On top of the scales, there is also a layer of mucus which offers another level of protection which is why you can feel the sense of sliminess when handling your tropical fish. The function of this layer is mainly to further protect the fish especially to avoid infection. That is why when you have an injured fish; the exposed skin area will become susceptible to a wide range of diseases. The colorful appearance seen on every tropical and coldwater fish is contributed by the pigmentation of the skin cells lying underneath the scales and how dense the buildup of pigment will actually determine the coloration of your pet.
Fins are very important to the fish because it helps them to maneuver and determine the course of direction it wants to head to. Basically every fish type is made up of dorsal fin, caudal fin (known also as tail fin), anal fin, pectoral fin and finally pelvic fin. Let’s look at the picture above that describes the location of each and every individual fin and then discussing in more details. Basically the fins has its own function whereby the dorsal and anal fin will provide stability for the fish to sustain its position in the water, caudle fin to provide thrust to push the fish forward while the pectoral and pelvic to will determine whether the fish swims right or left. Different tropical fish species has different size and appearance of the fins, some like the male guppy has a very huge tail fin while for the goldfish, certain variety like the ranchu does not even have a dorsal fin at all.
Eyesight, Hearing and Sensing
Different fish species has different eyesight capability. While most tropical fish has extremely good vision, some selectively bred coldwater goldfish has poor eyesight due to distorted eye position as seen with celestial goldfish. When it comes to hearing and sensing, almost all species can respond well to sound and vibration in the water. The ability is contributed by internal ears embedded in the head and the lateral line present on every fish allows it to detect vibration caused by movement in the water. In the wild, surviving native species has even more sensitive sensory organs to detect pressure waves in the water helping the fish to navigate across murky waters and avoiding obstacles.
Related fish topics:
Tilapia Fish Profile
Tropical Saltwater Tang
Freshwater and Saltwater Angelfish