Not sure what I should do...

[distaff]

They are doing fine all together. We just had one pass away due what we can only assume was due to moving away from the heat to drink and not being able to get back fast enough to warm up when we had very cold weather. She was very young but our older female seemed to have been depressed since her passing. Since we have had to put all 3 in one tank, she has been slightly more active, but has also been by one of our males sides constantly. The fatso has been left alone. We actually found him in the water dish soaking a little while ago. Should that spark concern in my case of him regurgitating? And per us getting paid again we will be getting a tank to atleast separate them for feeding. But I am not sure if my female would be happy if we separated them completely.

There are a lot of mistaken assumptions going on in this post.
You need some accurate info ASAP!
The best of luck to you.
Folks here, are here to help.

Basic care sheets are a good start.