i need help....(beginner on accident)

my friend threw a seed in a small flower pot of mines and a week later they started to grow....now 4-5 weeks have passed and the plant is about 8 inches long with only 8 leaves on it...is that normal? also i have the flower pot in the fish tank and the plant hs nearly reached the light because of the flower pot....could that be the reason of its slow growth? and last...i dont know the kind of seed it was..all i know is that the weed burned nice
any help and suggestions would be deeply appreciated

growing pot on accident? yea right......

yes its normal.

for the twentieth time today: not enough light.

8 leaves after 4-5 weeks? if you want to get bud from a plant then cut that down and buy a 250$ light, then you can grow