I have put some of our common creek fish in aquariums to practice on their care (before I try on more important fish).

I have a green sunfish in a tank with some large gambusia. I have a recirculating pump in the tank so it is a little "loud" with some water movement - like their original home in the creek.

I have been feeding the sunfish crumbled dog food (since that is what drew him into the minnow trap) and small gambusia from another tank.

Yesterday, I picked up some meal worms and dropped one in the tank. The sunfish instantaneously shot out of the corner and snapped up the meal worm.

I have dropped several edible things into the tank for the sunfish. His reaction to the meal worm was at least 10x more aggressive than his reaction to other forage.

I assume it was by far his favorite food item that I have placed into the tank.

How did the sunfish immediately know that tasty forage was floating at the surface?

Did the mealworm transmit chemicals to the sunfish's taste/smell receptors? (It was a 20 gallon tank and the sunfish reaction appeared to occur more rapidly than the rate at which a chemical would have diffused.)

Did the sunfish detect some particular movements of the meal worm with his lateral line? (The sunfish was at the bottom of the tank under the pump return flow, the meal worm was floating at the surface.)

Not important questions, I am just trying to learn more about fish behavior if anyone wants to add some general knowledge to the thread.

Thanks,
FishinRod