Help for using the fishidentifier for the Baltic Sea

Lumpsucker, male	Identifying fish is not always easy. Sometimes different individuals of a species look very different (e.g. male, female, juvenile) or different species are very similar to each other (e.g. sand goby and beach goby).
Lumpsucker, female	When using the fish identifier, it is important to always start with the characteristics you are really sure about. Maybe the small thumbnail looks a little bit different, but maybe it's just the colour? Fish can change their colouration during growth or depending on season, even within a few moments colour patterns can appear and disappear again.

Also through their behaviour, fish can sometimes show characters that are indeed different. Mullets and sea bass, for example, usually put on their first dorsal fin when swimming, giving the impression that they only have one dorsal fin. And sometimes characteristics change during growth. Whiting, for example, have a small barbel when they are young, which is then completely absent in adults. However, the fish identifier takes such features into accounts.

Wolfsbarsch

Finally, there are some fish with which even experts have difficulties to properly identify them. These are, for example, the small goby species, such as common goby and sand goby. And in the case of sturgeon, which sometimes enter the Baltic Sea as captive escapees, there are even hybrids, i.e. animals that are the offspring of two different species. In such cases, it is sometimes not possible to clearly identify the species..

Strand- und Sandgrundel

Last but not least, fish from other geographical regions can of course also stray into the Baltic Sea. In this case, the fish identifier cannot cover all possible species. If you have come across such a rare vagrant, please let us know.