your goldfish might die and maybe eat to much or the water starting to get dirty
they are dead
plastic plants are not harmful to your goldfish aquarium.
No you cannot put a frog with goldfish; goldfish belong with goldfish
Yes, goldfish can breed in the home aquarium.
yes
No, but gravel can help decorate and brighten an aquarium.
Goldfish and other types of fish do sleep. They do not sleep like people because they must keep moving water over their gills in order to breathe, but they do relax and go into a sleep-like state. They will chill on the bottom of the aquarium and won't move much. They will wake up and move around more if you touch them while they are sleeping, or if you turn on a light because they have no eyelids. This is why you should never leave an aquarium light on all night.
Because they are looking for food and may pick up gravel as they slurp their way along the bottom of the tank.
It will not matter. The only difference will be is that your fish will get bigger in the aquarium.
Just leave the aquarium at room temperature.
the answer is nothing ok
they can't
You should feed your Goldfish a maximum of twice a day for about 2 minutes making sure all the food doesn't sink to the bottom. If a lot of food does sink to the bottom be sure to remove it to prevent it from rotting in your aquarium which could case all sorts of problems.