Aquaponics is a food production system that couples aquaculture with hydroponics whereby the nutrient-rich aquaculture water is fed to hydroponically grown plants.
(https://cdn.shopify.com/s/files/1/2307/4917/files/NFT_Aquaponics-System_480x480.jpg?v=1701922958)
(https://www.mdpi.com/chemosensors/chemosensors-10-00303/article_deploy/html/images/chemosensors-10-00303-g001.png)
This is an amazingly efficient method to grow crops and farm fish. Of course, modern tractors and farm equipment give rural farming a pertinent edge. However, without these tools, there's a very strong argument that this would be the most productive possible food source. However, needless to say, it requires a lot of work to build. There would be a slight production chain in order to make this.
This would be a strong late-game method of gathering vegetables and fish. Especially in modpacks like MM9, fishing is lackluster compared to other food collection methods. So, it's hard to roleplay a seafood-based society like Japan or Norway.
This is a good example if you don't require a massive production.
Maybe there is a way to make it for a smaller settlement. It would
fit into my Out of This World mod, which only has a fisherman and
some greenhouses.
It looks complicated in the picture, but all things are a one-time
investment. You do not have to specifically build an air pump or
a sediment tank. There are resource chains in CC or RKEC that can
be used. (MM is even better)
Good Luck with planning. :)