Traditional way to grow fresh water fish
Having different types of fish in your system in different tanks can help play out a more natural eco system eg.
There are three basic types of freshwater ecosystems:
Lentic: slow moving water, including pools, ponds, and lakes.
Lotic: faster moving water, for example streams and rivers.
Wetlands: areas where the soil is saturated or inundated for at least part of the time.
we use the strengths from each of these to put together to from a ecosystem that is device and does not require so much input from us
even though the duck weed grows from the nutrients in the water it still adds to the total growth
we use Carnivorous fish in aquaponics can serve alot of reasons
they will keep your level of population down
its better to have more fish than you need and have to kill some than to not have enough fish and needing more. so your breeding program should have plenty extra fish left so instead of through them away you will just feed them to tour carnivorous fish to keep that energy in the system.
not growing fast enough or not the correct shape
if you have slow growing or deformed fish that are a drag on the feed conversion ratio you should feed them to the carnivorous fish in order to keep the energy in the system and not let it leak out through unusual streams like this one.
Increase the range of feeds you can use
you can add a meat source to your inputs what this does is increase the range of feeds you can feed your aquaponic system and also the different types of micro nutrients that will become available from feeding meat to the system sometimes.
we don't recommend feeding meat of sick or disease fish to your aquaponic system as these may carry harmful things with them and do more harm than good. but this is up for debate.
like the pacu are know to eat wild fruits and can add a nutrient line into the system that favoured growing fruiting crops so spoilt food can in theory be feed straight into your system.
they can also eat water based plants and even some types of sea weeds.