Kuhli loach won’t stop panicking

I recently bought 4 kuhli loaches, 2 black and 2 normal. I bought one of the normal kuhlis 6 days ago, I was planning to buy more but they only had one left in stock who was still quite small. I bought it and left my phone number for the store to call me when they get more in stock. I had also been looking at a different aquarium shop online who also sold kuhli loaches a lot cheaper, but there were also out of stock. This aquarium shop is quite far away but also pretty big and popular. A few days ago I checked the website and they had the loaches back in stock. Yesterday (Saturday 14th) I went and bought one normal kuhli and two black ones. I have them in my 45-50 litre tank with my betta, who is very docile. This morning when I turned on the light, they all scurried away except Nelson, the kuhli that I have had the longest. He started panicking and darting all around the tank and up and down the glass. I turn of the light in the hopes that it might settle him but it didn’t help and he’s been swimming around and panicking for almost 6 hours. Any idea what could have caused this or what I could to to help? I have separated the betta in case that is what’s stressing him but I have seen him swimming around and foraging with the betta right next to him so I don’t think that’s the problem.

 

Probobly the new guys are stimulating him, worrie? stress? confusion?
Do you have multiple places for them to hide?

 

Yes I have many places all around the tank for him to hide but I have seen him hanging out with the new loaches happily (or just looking happy) so I don’t know if that’s what it is. Either way, is there anything I could to do to help calm him down. I’ve covered the whole tank in blankets so that he doesn’t have any extra stress from things in the room. Even with the blankets, I looked in once and he was still swimming around everywhere. Do I just give them time or do I need to seperate him from the others somehow. I don’t want to do anything to cause Nelson any extra stress but he is clearly already very worked up and I don’t know what the best option is. He has barely rested in 7 and a half hours
I just checked again to see how he was doing and he had stopped swimming and was hiding, so I carefully took the blankets off the tank and he was fine. I left then came back 5 minutes later to find him swimming again. I’m going to partially cover the tank so Nelson feels protected but so I can also watch to see if I see what’s setting him off. He was just sitting on the floor, but then he suddenly darted away again. These are my first kuhlis so I don’t have anything to compare their behaviour to. Do kuhlis ever have a “runt” of the shoal? Because Nelson is by far the smallest is it possible that the new ones might be intentionally scaring him? From what I’ve read about them, kuhlis are always placid and social with other kuhlis.
Also, Nelson has still been swimming but he’s clearly getting exhausted and he’s taking short breaks very frequently, often near the new kuhlis, who don’t seem at all hostile towards him.

 

I’d say he just needs to settle in. The khulis at the store I work at freak out if they don’t have cover. They even bury themselves down into the gravel.

 

That's quite normal

 

thank you all for your advice I was a bit freaked out when he just didn’t stop. He seems a lot better now but he is still very skittish and even just walking past the tank can set him off. I’m sure Nelson and his friends all say thank you too! I’m going to make some more decorations for them to hide in soon so hopefully that might help settle him. Thanks again!