I wouldn't worry unless he stops eating all together. It could be just because he's new and not accustomed to his surroundings yet. My betta is such a little pig, that he's so busy swimming back and forth across the front of the tank when he sees me walk up, that I have to stick the tip of my finger in the water to let him know where I'm going to drop the pellet otherwise he missess it completely and it eventually sinks. This way of feeding isn't so bad because the benefit is I watch him eat each pellet, I know exactly how much he's eating and I know there are no pellets rotting at the bottom and dirtying up the water :)
Oh, and he might not be "eating" the gravel as much as exploring his new surroundings... they can be very curious
Last edited by Greylady; 07-29-2012 at 12:38 AM.