Ricky, you should be able to find algae wafers (or sometimes called algae discs) in any pet store. They sell them mostly for catfish, plecos and such.
They are good because they are mostly made of vegetable matters like spirulina, which is basically "solid algae". The initial wafer/disc can be a bit hard, but after soaking or breaking in smaller pieces they are great for fish. Easily digestable and great for their intestines, as they aid in swim bladder troubles and floaty issues a lot of times.
Package can look similar to this....
Hikari Algae WafersOf course, other companies make it too - you should find the Wardley brand at Walm*rt...