The tank has been up for a year and I've had this dwarf puffer for about as long. He has always come up to the top and ate blood worms that I held for him very heartily. About 2 days ago though I went by the tank and he didn't come up to the top to greet me like he always does. He sluggishly came up to the top, but he was having trouble grabbing the worm. Finally he was able to grab one but he couldn't eat it all and spat it out. Now he spends all of his time just sitting on the bottom not moving at all and he has no interest in eating.
He is the only fish in the tank. There have always been trumpet snails in there for him to eat.
Planted 10g tank
weekly despite low nitrate levels