My freshwater puffer died suddenly, any idea why?

Question

I have a very stable tank and have had it for about 1.5 years. It is 65 gallons with a mixed population of semi-aggressive fish. He was very social and responded well to me especially, actually didn't do well with others. He seemed to prefer dried kril shrimp broken into smaller pieces. For the most part, he was hand fed or he swam up a short tube to eat or the other fish would bully him or take the food and he would not even try to get his share. I have had him since Christmas. He seemed fine on Saturday, I woke up Sunday morning to find him dead. No obvious wounds or signs of impending death. He was adorable, would come to the aquarium front when he heard my voice or saw me walk by, fins flipping like helicopter blades, fanning his litte tail fin to its widest, and puffing ever so slightly to show me he was happy I was there. I miss him very much. As a fairly new aquarium owner I just want to make sure I didn't do anything wrong. Water checked out perfect. Any idea?

Now I feel terrible. I was told by the pet store where I bought him that he was freshwater and that there would not be a problem adding him to my existing tank. Makes me feel horrible that what I did lead to his death. The only thing I could get him to eat was the dried kril. Thanks to all for your reponses, I learned a lot. :o(

Answer 1

There is really no telling what happened...no need for guilt or blame. From what you tell us he came from a fresh water system...the fish should have been acclimated already...go back to the store and check on where the puffer came from. (Your vendor has a recieving list from his wholesaler, no matter what he might try to tell you). If there are still puffers for sale, watch them closely and see if you can see anything suspicious...little white spots, fungus, bad fins, dying fish, etc...and see if the vendor has had any more reports of dying puffers, or has had them die in the store. Fish purchasing is tricky, at best. And the fish in stores are generally so stressed that many of them never make it.
Hard to say what happened really. Take care, and if you are going to keep fish you need to know that this may happen to any fish you buy. Steel yourself, and do the best you can.

Answer 2

Well first off him puffing wasn't his happiness, they only puff if they feel threatened which he most likely did.

Anyways the only freshwater puffer is a dwarf puffer, the rest are either brackish or salt water, so that most likely contributed to your puffers death. If it was a Green Spotted Puffer (green on top with black dots) and if it was bigger than 2" and still in freshwater he definitely died because of it.

Puffer fish are very "cute" I've had a few in brackish waters and they live long, and they are responsive. Most likely he died because

a)fresh water
b) stress from water
c) did you only feed him krill shrimp? he needs a good variety of diet so that might be it also.

Answer 3

He was probably just stressed from the bullying. Just a lesson you have to learn. Puffers do best in a species tank (where there are only that one species of fish in the tank), but I have heard they do well with Otocinclus (Otto) Catfsh. Sorry to hear that. They are pretty adorable though!

: (

Nosoop4u

Answer 4

Puffers are a brackish water fish. Was your aquarium set up for brackish? Puffers as babies are community, as adults are very aggressive and kill, fin nip other fish.
Brackish is where the ocean (saltwater) meets freshwater streams. It is a combination of the 2 waters. A puffer has to have a semi-brackish to brackish water. Good Luck!