Should you get the excess food out of your fish tank?

yes! unless you have an algae eater, fish don't like it when you have leftover food, fish foods spoil a lot in water

Excess fish food will sink to the substrate and decay. This decay will create nitrates that is bad for your water quality and your fish. To reduce the amount of food in the substrate feed your fish less food and replace 10% of the water in your aquarium every week. At the same time vacuum your substrate to remove the excess food and fish waste.

To prevent excess food only feed your fish once a day and only enough that they can eat in two minutes. I do this in the morning then give my 15 fish in a 75-gallon aquarium a cube of blood worms at night.

See link below there is a video on how to vacuum your aquarium to remove the fish food.