Yes, there is a chance this could be OCD.
OCD
They eat food any normal person would
It's doubtful. OCD is about repeated habits so, possibly one of the problems is someone eats a small or large amount of food because of the OCD. Some people with OCD will refuse to eat certain foods or will move their food around on their plate and eat in sequence (eg: meat first, then potatoes and then the veggies.) This is a "ritual" and generally doesn't change unless the person receives therapy.
It can be a sign of OCD, but only if it was extreme. For example, separating things such as tomatoes from pasta, not being able to eat the meal at all if food is touching, etc.
Don't eat the food that you are allergic to. Keep all the foods that you can eat separate to those that you can't eat (no cross contamination). Take an antihistamine.
S Meyer's vampires don't eat real food. It apparently tastes like ash or something equally awful. I somehow doubth any vampire would eat human food, let alone chocolate.
Well, you should give them two separate food and water dishes. If that does not work, you may need to separate the birds at feeding time.
As soon as your pet mice are weaned, or will eat solid food and do not depend on their mother, immediatlly separate the males and females. This shows signs of maturity and the males and females will soon start to breed.
Cats may take food out of their bowl to eat because they prefer to hunt and eat in separate locations, mimicking their natural behavior in the wild. This behavior can also be a way for them to control their environment and feel more secure while eating.
How would ask this question? Answer: Stupid people!! :)
Try and separate those two fish from the rest of them. Place them in five separate containers for feeding time.
Feed them in separate spaces. The one is trying to dominate the other.