Adding fish

Question
Recently I set up an old 20L fish tank. I added 4 neons on the recommendation of the fish shop guy, then a few days later a siamese flying fox. I would now like to add two guppies, but I am wondering how long I should wait before adding any more fish?
Also I was sold this flying fox under the name alage eater. I later did some research but could not find out whether flying foxes eat alage. Do you know of any useful sites that could give me some information on the flying fox?

Thanks,
Sav

Answer
HI Sav,
Thank you for your letter. Here is my guide for holistic aquarium care:
http://steamboats.com/aquarium.html
If you use the product "Cycle," it will speed up the process of setting up the tank. Cycle is friendly bacteria that helps with the fish's digestion, silky coating, and to break down fish waste in the tank.
If you buy Cycle (or its equivalent), follow the instructions on the bottle and store it in the refrigerator to use for future water changes.
re. the algae eater. It will eat algae, but probably will expect to be fed with everyone else. Limit food to one or two flakes or pellets per square inch of fish per day.
If you want to discuss further, please write back.
Nori