Siamese algae eaters are frequently aggressive. It might be exacerbated by hunger but it's not the sole cause. As for the eel, he may eat some scraps that lay around but I wouldn't count on him to be the tank's janitor. Even if you find a fish that will eat all leftover food scraps, you will still have to deal with detritus, and that's something that no fish will eat. The best way is to have a power head or other water-mover to stir up the waste and get rid of dead zones.