I feed my Oscar those orange food sticks, and he really likes them. But, he will suck one of them into his mouth, and in about 3 seconds it looks like he's burping, and a bunch of little crushed up pieces of it will come back out of his mouth and his gills. Then, he just grabs another one and does the same thing. It almost looks like he's just crushing it up and spitting it out. And the bottom of his tank always looks like I've been overfeeding him when I haven't been. Is this how Oscar's eat? Why does he spit everything back out again?