Kind regards everyone

Hi Victor,Viktor Jarikov wrote:Sorry. Not familiar with wave makers, only heard of them.
synos have this as well in the spot in question.The spot between the eyes is special AFAIK and what you observe, I believe, is normal. Doradids for instance have a light sensor spot between the eyes aka "third eye", that's actually responsible for many hormonal functions. IDK if it is the same in synos or most/all fish.