Pink spotted shrimp goby scared or dying? or just weird.


Reefing newb
I don't think its a coincidence but i recently got a pink spotted goby at my LFS and it was immediately attacked by my maroon clown. It was the second time I tried putting a goby in ( the first was a diamond goby) and the clown attacked it. So I decided that it was time to take him in for some credit. After 2 days of being in the tank together the gobies tail and bottom fins started getting chewed up and he started laying in this overgrown green algae I'm letting grow because i have baby peppermint shrimp living in it. I figured he was just laying there for food but i went to move him with my net and he was very lethargic and didn't even try to get away so pulled him out and separated him into a little temper ware. After about 24 hrs (I was changing his water about every 3hrs because there was no filtration) alone he got better, started moving and eating again. So I got him and the clown fish bagged up and took both to my LFS and asked the lady if she would hold on to the goby for couple days in hope he would get more comfortable since thats where he came from a couple days before and she said thats fine. And i traded the maroon in for two little ocellaris clown fish. Small, one about a quarter size the other about a dime. They were Inseparable the first week and now have started moving a little apart. IDK what that means, But back to the issue. After being returned to my tank from spending some time at the LFS he was acting a lot better without the maroon in the tank but then started hanging out at the top left of my tank by the return basically touching the surface. The diamond i had started doing that right before he died. The one currently in my tank is eating every time i feed and is moving around some times but is he dying? Why is he up there? I feel like he's following in the steps of my diamond that died up there. Also when he was at the LFS he was paired with a pistol shrimp so i took it home with me too and they hung out the first day and have separated since. Any idea what it could be? Is it my tank? Help please. I don't want to lose this guy too. Thanks
Thanks for all the help everyone. He ended up pulling through and settling down and meeting back up with his pistol shrimp. So all is good in the tank for now. Idk what it was. Probably just time.