i have a 5.5 gallon tank in which i have my alfred, mable, 6 albino corries and 2 guppies.
on another website - www.thinkfish.co.uk you can do a community creator, which i did and the only thing they said was that the guppies may nip Alfred's tail.
the guppies do not, they stay well clear of Alfred. and all the fish are living happily together.