pretty pathetic looking herbs

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

you answered your own question when you said your friend threw a seed in a "small" flowerpot........it may be rootbound,transplant it into a bigger pot and see how it goes....and the light has nothing to do with slow growth.....good rule of thumb is the more the better,its impossible to have too much light unless heat is an issue