For a better understanding of our finned friends
We can tell an incredible amount about a fish species from its body structure, mouth position and shape, as well as its fins, without ever having observed it in the wild. This, in turn, helps us to set up the aquarium correctly, to socialise the fish properly and to feed them appropriately. Because, as with humans, nutrition plays a very decisive role in health and, in the case of fish, in colour formation as well.
The upward position of the mouth suggests that these fish eat at the surface. In the course of evolution, they have adapted to snatch insects that, say, fall on the water surface. However, this food source is never sufficient in the wild, and so fish with this type of mouth can also pick up food in front of them or below them. Only for the surface are they specialised and superior to other fish species.
Suitable food: floating JBL flakes & sticks & treats
This mouth position is the most versatile and suggests that the fish eats food from the open water (e.g. plankton or small fish). However, it can also feed at the bottom or on the surface. For many fish species, the availability of food varies depending on whether it is the rainy or dry season. During the rainy season, many fish even eat fruits, which are then accessible to the fish!
Suitable food: sinking (i.e. moving) JBL granulates
If the mouth is on the underside of the body, you can be sure that these fish eat on the ground. In the case of armored catfish and loaches, the fish also have barbels with which they can feel for food at the bottom. Sucking catfish use their inferior mouths to scrape off food, but also to hold themselves in place, as they often live in water with a lot of current. In display aquariums, you can often see rays even picking up food from the surface by turning onto their backs. Fish are actually quite ingenious!
Suitable food for bottom dwellers: JBL food tablets, wafers