I came across periphyton-based aquaculture a few years ago, while researching options for a fishery development project in Nigeria. Rather than try to explain it here, I will refer you to this document, which does a better job than I could (or do a quick internet search on your own):
One method used to improve productivity is to stuff manure into the hollow center of perforated bamboo which then leaches out to feed the periphyton. If you are adding nutrients, you need to be careful to maintain a proper balance.
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