All herbivores need algae in their diets. However, virtually any fish will enjoy an occasional offering of algae. If you don't have fresh algae, the next best thing is algae flakes or wafers. Algae wafers are the best option for bottom feeders, while algae flakes are an excellent option for community aquariums. Here are my top algae wafer choices.
1. Hikari Algae Wafers
Hikari makes the top of the line algae discs and wafers. They do not cloud the water, and come in a sturdy resealable pouch. They do cost a bit more than the Wardley algae and spirulina products.
2. Wardley Algae and Spirulina Discs
When it comes to algae and spirulina wafers, Wardley is very comparable to Hikari. Like Hikari they come in a sturdy resealable pouch. I have found they can cloud the water, however that problem can be avoided if uneaten portions are quickly removed from the tank. Price wise, they are very competitive.
3. OSI Spirulina Wafers
OSI makes a full product line of foods for Marine and Freshwater fish. They offer both spirulina wafers and pellets packaged in 3 oz and 6 oz screw top cans.