Well last week I lost my dwarf puffer suddenly and now my HMDT is acting very lethargic laying on the bottom of the tank. I think he is dying. I did a water change and a few hours later, he seems not good. I changed the tank next to his and that fish is seemingly fine. He has been dealing with some fin rot that is very persistent. Also I figure him to be about 2 or 2.5 years old. Ugh why does it all happen at once? Things were going so good for a while. I lowered the water a little so he can get to the top and also in case it maybe got contaminated but like I said his neighbor fish seems good. I'll keep updates of course but I'm pretty sure he is a goner just based on what I am seeing.