Aquariums: Puffer suddenly terrified? What could I have done???

My topaz puffer seemed to be doing so well, maybe 3 days ago we put a live ghost shrimp in his tank for feeding but he hasn’t seemed interested I feel this may be the issue. I’ve seen my puffer attempt at hunting sometimes since we added the shrimp but he’s never succeeded. I also assumed the shrimp would die because it’s in saltwater but it’s somehow survived and I fear it’s causing my puffer extreme stress. Since I added the shrimp his belly was darker until yesterday he pooped and I did a water change and he was white and happy as ever. I went to feed him this morning and he was darker again but still happy to see me and spitting water at the top and acting how he normally does. I feed him with tongs because he doesn’t seem to eat any other way, he won’t even go after it if it drops to the bottom of the tank- again he only eats from the tongs. Halfway through feeding today something seemed to scare him and it scared him bad he immediately lost his color and his belly turned dark and I tried to offer him some food, from tongs, to attempt to ease his worry and it only made him freak out and hide between the heater and filter. I’m at work now, this all happened right before. I’m going to go home when my shift is over in 3 hours and take the shrimp out of the tank, because I think its presence may have a part in this. But I’m so worried about what else could have scared him. I’m posting this about 2 hours after the incident which is also about the time the video takes place, and he’s still scared and dark and has dim colors. He’s come forward more in the tank and isn’t crammed in the back anymore but I’m still so worried about him and I really don’t know what could have scared him. He’s very used to the tongs and being hand fed and he’s even bitten the tongs quite a few times so I don’t think that’s what could have scared him but I just don’t know what happened. We’ve put towels over his tank to limit light and try to make him feel comfortable, that’s about all I know to do besides take the shrimp out but I won’t be able to do that until I get home in a couple hours. I cried the whole way to work we recently lost a porcupine puffer and I don’t want to lose my topaz he’s my pride and joy and I love him dearly any help is appreciated.

TL;DR

I think my puffer was scared by his feeding tongs today, OR the live ghost shrimp hanging around in his tank he hasn’t eaten. Normally when he sees us grab the tongs he knows it’s for food and he gets excited but something terrified him today during feeding and I’m lost on what could’ve happened.