Tilapia: biology, culture, and nutrition By Chhorn Lim, Carl D. Webster states that nitrate is not toxic to Tilapia whatsoever.

We should start a library on this dang forum to allow members to check out books. The following book would describe just about any issues regarding toxicity of fish: The toxicology of fishes By Richard Thomas Di Giulio, David E. Hinton

I already have a list of 6 books that are MANDATORY for my research and education on aquaponics, and these books cost $997 shipped total. Obviously, I am buying them 1 at a time, but it's still a lot for 1 student to pay for... my library card is maxed, any some of the newer or better books are unavailable to me.