Beside head and eyes ratio need to be similar and the eyes won’t be too large (stave or old age) ,to pick a Juvenile arowana eyes, it is something that is the most hard to identify. If only looking at their body shape , it might be hard to see the eyes might have the possibility to have the drop eyes problem. But some of the arowana’s eyes might still stay alright even if their eyes shape aren’t the best, and some arowana that is fear of light can be able to notice after open up the tank in order to observe their performance, since usually the tank stay close and after open up they might start swimming sideway. Like from the writer saying that eye drop problem is because of their innate gene that is sensitive to their environment and the acquired factor of the environment affecting them. They specify them into five type which being down-looking type, photophobia, fat type, concave type, interactive type, and only for fat type it was affected by both innate genes and the acquired factor(see if it hard to accumulation) ,however the other types will only because of innate genes to cause those problem