Yes it is unusual, I got some Betta pellets from Pet Barn, That night as I said he put on his usual feed me display, I fed him 3 pelets of the new stuff, He scoffed them down and did his I want more by swiming around the tank flaring a bit looking cute, All was well, He swam off into his plants when I went to turn the tank light off he didnt realy come out to say good night. In the morning he was in his sleeping spot among the floating fox tail dead. I cried. I gave his body to my Pitcher Plant.
When I went to my local fish shop, R&J Aquatics, I was telling the guy about it, he asked to see the pellets, so I took them in, The guy said they were out of date by nearly 6 months and did not smell "right".
I threw out all the food and treats I had for Microsoft, and got fresh stuff from the fish shop, The guy even had me bring in a sample of my tank water that he tested in the shop everything was fine.
Then he gave( not sold but gave) me Yobbo, And sold me fresh food and treats for him. I also got a few big silk plants from the shop.
I do not know if it was the food or not. However I am never going to buy anything from Pet Barn again, This is the second time they have sold me dodgy products, The first being that verigated plant Bettarazzi
Warned me about here,
http://www.ausaqua.net/index.php/topic/15869-my-2-foot-betta-tank/?p=176956
From now on I will only buy stuff from the Aquatics shop, He may be a bit more expensive, But the guy has 5 display tanks with bettas in them, and he wont sell you stuff unless he uses it in his tanks. In his shop you wont see anything with " Fix " on it eg Bettafix. He says there is no such thing as fix in a bottle. Good clean warm water, Good food, Indian Almond leaf, Is all you need to keep the fish healthy.