Is it a right choice of UGF for a planted tetra tank of size 4'(L)/2'(W)/2.5'(H) ?

I am making an aquarium of the above size. Someone who is guiding me suggests to make it heavily planted tank for Neon tetra. From his experience he is saying that tetras polute the water very little and UGF is enough for it. He is a professional supplier of aquarium and fishes. Please tell me whether he is right or not. Pl. tell me other choice of fishes keeping the plantation and UGF constant.