I feed him silversides and shrimp.
What else have you been feeding your lion?
Are you soaking the foods in vitamins?
What kind of shrimp are you feeding and are you leaving the shell on?
Are the eyes clear or cloudy?
How often do you feed your lion?
Are you feeding Live foods?
I am guessing the fish does not have lockjaw because it wants to eat but can not. Your lions Diet is very important, a lack of nutrients can lead to premature death yet so can over feeding.......
Feeding fresh water fish can cause fatty liver disease / fatty degeneration of internal organs, vision failure & in time they will be unable to swallow or can develop Lock jaw which can lead to starvation.
With that said a lack of nutrition can also lead to a lion that is unable to swallow, vision failure and lockjaw.......
This lion needs a variety of food - Octo, Squid, Raw Shrimp, Scallops, Ocean White Fish, Crab, Frozen Sand Eels, Silversides are fine but not all the time, Raw Shrimp with the shell left on....... You lion also needs foods that are soaked in vitamins.
Sorry for all the questions, we need to narrow this down........
Kaye