This all starts from a fish ailment you're trying to diagnose as a mental illness. Best of luck in your aquatic endeavors with that methodology.
The finned aquatic creatures we group under the title of "fish" are actually not all that similar to each other. To go back to my previous example, it would be like assuming that we terrestrial creatures have similar attributes just because we all happen to share the same habitat. Humans, giant tortoises, horses, hamsters, and salamanders are not closely related. We don't share a common ancestor. Well, neither do fish. Fish have not been as closely studied as mammals so we don't know yet what their cognitive abilities are but it's not impossible that at least some of the species are capable of experiencing emotions of some kind.
Could you link this study please?
while this is an interesting read it is disturbing researchers gave zebrafish so MANY drugs to get some of these responseswww.springer.com/cda/content/document/cda_downloaddocument/9783319337739-c1.pdf"
Developing Zebrafish Depression-Related Models by Julian Pittman and Angelo Piato
Springer International Publishing AG