Many chaeto species are eaten by people, but I would strongly recommend against eating anything from an aquarium due to potential for microbial and toxin (e.g., heavy metal as well as organic) contamination:
http://uses.plantnet-project.org/en/Chaetomorpha_(PROSEA)
Well having just done some (very small scale) testing of caulerpa and gracilaria consumption I have say..... garshdarnit, why didn't I read this before!
Seriously, thanks
@Randy Holmes-Farley and this is a very important thought. I presume the problems are
a) we don't know what the supplements the companies put into their salt/trace elements
b) we tend to have relatively high bioloads leading to a much higher level of different microbes?
Fair enough. Few questions just for my understanding then, to either Randy or anyone else with scientific/aquaculture backgrounds (to include
@Subsea @AquaBiomics and plenty of other people I can't remember OTMH - as one can clearly see from this post my knowledge of this is 0):
1. if we used only natural seawater from a good source, I assume we would lose the toxin contamination problem? For that matter, I'd imagine that some of the big salt companes (e.g. IO) is used rather heavily in inland marine aquaculture (assuming aquaculturing any marine fish in condition where you don't use NSW is financially viable)
2. I believe algae aquaculture (kelp, nori, wakame,etc.) are pretty intensely cultivated? How is microbial contamination avoided in such situations? Are they cultivated in fairly clean areas without a lot of runoff or large fish populations? And as an aside, if you had a dense salmon farm producing all kinds of wastes, then it would not be recommended to feed a wakame seaweed far based off of the salmon's waste?
wouldn't eat anything from the tank either, but the tiger perch might end up as food if it grows too big. Deep fried, covered with garlic oil, a few drop of sesame oil, deep fried ginger slices and a few table spoon of sweet soy ketchup seems promising. 
