Super stressed betta and kulhi loaches

[mtnmonster]

I can't get pictures without chasing fish out of hiding spots, but they're obviously very stressed. Lethargic, hiding, not eating, the betta seems like his slime coat may be coming off his face. No visible injuries. 

So far I've been doing water changes every 13 hours and I think the cycle crashed when I added some new fish. I lost the 3 new guppies. They had a stressful ride home from the lfs. I had car trouble and they was in the bags for 2 hours. I kept them as warm as possible and when I got home I let them acclimate to the quarantine tank before releasing them. I realized my quarantine tank had a crack and was leaking very badly so I decided to move them to the tank since all it had was a healthy betta. But when I started putting the bags in the tank to float I noticed water felt cooler than normal. Heater stopped working. All petstores were closed and I bought one from Walmart and it slowly brought the tank up to 79F. The kulhis and the guppies seemed fine but the betta didn't like the bags. After I released them the kulhis immediately hid, like normal and the guppies were acting fine. The betta, who lived peacefully with guppies before decided to attack the guppies. I placed him in a small breeder box until I could figure something out in the morning.

Before I left for work I checked them. Everything seemed fine. Used a test strip and water seemed good. When I got home I checked and one guppy had died. Check water and it was fine but everything seemed off. I tested for ammonia and nothing. I just figured it was stress so I kept lights off and waited. A couple hours later the 2 remains guppies passed. I checked water again everything was fine but a massive ammonia spike happened. I immediately change 60% of the water. A few hours later changed 50% and now detecting no ammonia but nitrites are .5

Betta was in his little box and I let him go since the guppies were no longer in there. He swam a bit and now is hiding. No signs of 1 the kulhis and the other has been laying under a pebble just breathing for about 24hrs now. I don't want to really dig around the gravel to find them and disturb the water anymore for now.

I'm not sure what else to do except keep checking water and changing as needed. Would a little aquarium salt help? I've used it for stressed fish before but not with bettas, kulhi loach or mystery snail. The snail seems to be the only one not ill

[xXInkedPhoenixX]

My understanding is Kulis don't do well with salt, neither will your mystery snail. Do you not have any used media you could set up a temporary holding tank for the new loaches? 

[Colu]

What I would do is small daily water changes and add prime to detoxify any nitrites and ammonia every 24hr the peeling or over production of the slime coat your seeing could have been caused be your ammonia and nitirte spike   you could add a small amount of aquarium salt 1 table spoon for 10 gallons that shouldn't affect your mystery snail or kuhli loach I wouldn't add more then this if their still not eating after a couple of days I would treat with maracyn it's safe to use with snails in the tank

[mtnmonster]

Thanks for the replies. Things are improving in the tank betta is looking better and the missing kulhi was found acting completely  fine. The other is a little lethargic still. I've not detected anymore ammonia and just nitrites. Still doing 50%water changes every 12 hours. But the last test nitrites were much lower. All plants have suffered pretty bad. Almost all completely melted. I'm trimming and removing a dead plant matter. The betta is eating but still very aggressive.  I had to temporarily move the mystery snail to another tank because the betta was relentlessly attacking it. Not sure what is going on with him just very angry lately. Its like when he first seen the guppies a switch flipped. He don't like the kulhis either but they're able to hide pretty well. I guess he's going to get his own tank soon.