I believe you will need to get the system setup with fish before adding in the plants. The tank will need to "cycle" before it starts to produce plant food. Most fish stores will carry a "freshwater master test kit" which can help in knowing if the system has cycled. Starting off with a small amount of fish works best to get the bacteria started. The first bacteria will change ammonia(fish poop) into nitrites. Both ammonia and nitrites are harmful to fish in high amounts. After you have nitrites in the system another bacteria starts changing nitrites into nitrates which are almost harmless to fish and that is what the plants will eat. Starting with a small amount of fish helps keep the ammonia and nitrites from spiking to hard while the system is setting up. Once ammonia and nitrites are back at zero you can add in more fish. Plants can be added after nitrates are present in the system.There will be a ebb and flow table that is controlled by an over flow siphon. The "table" will be separate from the fish tank and have the veggies in it. I think you brought up a good point, the plants will need to be established first before adding fish.
I guess I'll have to do more research on growing tomatoes in aquaponics. They also seem to be heavy feeders.
I think my family member said that the fish would go in first, and there shit would cause a jump in nitrates that would be unsuitable for the plants. But having some common pond lily's would help stabilize the water and make it possible for the plants to survive. This is really an experiment we are doing and neither of us have experience. Just have read enough information to know how the system works. When things are up and running I'll take some photos and post them probably over in the gardening section.
??? Mine is setup in a small cabinet. I want to make a 10 gallon fish tank stand with a micro setup in it. Just pump the water up into the tank from the grow bed in the stand and let it overflow back down again through some pipes. Completely stealth and concealed.wont work in my 1br lol