Can you imagine a fully transparent fish, that have skin so light that you can see what's inside them. Although it may be hard to believe, there are some types de peces with completely transparent body. And although it is not very common to find them, since they are mostly used for scientific studies, let me tell you that they do exist.
One of these transparent fish is the Barley, which was discovered in 1939, but it was not until 2004 that scientists managed to collect enough information on this type of species. That same year, scientists from MBARI, Monterey Bay Aquarium Research Institute, managed to record this specimen. The Barreleye is characterized by having a completely transparent part of its head, while its body is the same as that of any other common fish.
Another of the transparent fish that exist is known by the name of crystal catfish, which lives in tropical fresh waters. Although many people do not know it, this type of fish has become one of the most famous and rare fish in the aquarium world. If you plan to look for a fish of this species, I recommend that you raise them in a group, since having them all swimming together is absolutely beautiful.
If you are interested in this type de peces transparent, it is important that you also know the Indian Glassy Fish, which lives in fresh waters and can also live in an aquarium. It is important that you be very careful when acquiring this species since they usually inject colors to make them more striking, but this only causes allergies and diseases.