Betta Fish: My betta in his 54l tank

I’ve had Finarfin for a bit over 7 months now. He’s constantly active, exploring every inch of the tank.

I tried adding a few Amano shrimp a while ago, but that didn't go very well. He flares at them, and chases them if they flee from him.

They now stay mostly hidden during the day and only come out at night to eat. I probably should have guessed this outcome, given that Finarfin even flares at me sometimes when I approach the glass. He's definitely on the aggressive side, even for a betta. A tiny part of me still hopes that the Amano will venture out more, once they're fully grown.. but probably unlikely.

I guess this could serve as warning that not even Amano shrimp are safe with some betta.

(I have a lid on the tank, but removed it quickly for the picture)