Yes. Contrisoil will "absorb" (more accurately hold closely) nutrients such as Ca, Mg, Fe, etc. It does have some micros, but it's not enough to run a long time without dosing even micros. Beyond that, it definitely does not provide macro nutrients such as K that your fish and food you feed them will not provide.
Just dose regularly and let the soil provide what it provides. The plants will choose to uptake through whatever method they prefer.