We have 2 oscars bought young a few months ago in our aquarium. Lately one of the oscars is finding difficulty to eat. The other oscar is eating the extra food we are trying to feed her and so ine of them is huge compared to the other. The small Oscar seems to jump to the surface to gobble the food from the sides of the tank instead of eating it smoothly like it used to and is mostly missing her target. Any suggestions please? Tried to isolate it but still to no avail.