My tank is actually a 37 gallon. My mistake. The 37g tank is a grow tank for my smaller fish. The goldfish is fine in the 78 degree temp, I had him in my 150 but my oscar likes the taste of his tail. I do not put more than 1 tablespoon of salt/5 gallons in my tank and that will not severely affect my loach. I bought the LFS last loach, but they have another one with my name on it on the next order. I put salt in all of my tanks with no negative affect. He will only be in this tank until he can grow another inch or 2 and he'll then go in my 150. I know how big all of my fish get. Thanks for the interesting pic, but that shark is over 10 years old. Mine is about 7 months old and 3 inches. These sharks grow very slowly. I also have 2 pacu, and yes I know how big they get as well. I would not purchase a fish without researching first. My 37 gallon is only being used as a temporary tank for all of my smaller fish. I understand that the puffer is not a community tank fish, but as long as he has his own hiding, and all of the other fish are not aggresive but can defend themselves, there will not be an issue until he requires more salt in his diet (Which I have a 55gallon that will be his new home).
The ich med was used at half dosage, I treated the tank 3 times in a 3 day period, I also did a 25% water change after each day so the ich med would not build up. When I got him from my LFS, they had the tank on hold for over 2 weeks, So it seems that their treatment was not complete when I received him. The puffer no longer has ich and has not shown any signs of stress from treatment. I am very careful when treating for ich.
I can not limit how many ghost shrimp he eats. He only seems to eat one a day and the next day he poops it out and eats another. But he seems to always pick up the biggest, fatest, ghost shrimp in the tank. Surprisingly, being the smallest fish in the tank, he has the largest poop. As for filtrations, I have 2 60 gallon HOB filters and I do a 30% water change weekly if you are worried about the goldie and the puffer being messy. I am already aware of everything you have told me, but I have taken all of the nessacary precautions, but thank you.