One of the main difference between backyard aquaponics and intensive agriculture/aquaculture reside on the fact that we create an environment where living creatures are living in comfortable condition. Unlike the classic food production system we aim to not spray pesticides but to offer the best environment to our ecosystem to avoid the stress and the apparition of disease.
Water parameters are massively important for your fish health. In the nitrogen cycle the bacteria are transforming the fish poo (ammonia) in nitrite and nitrate. Ammonia and nitrite are highly toxic for the fish and we want to make sure we keep them at the lowest concentration possible (below 0.5ppm).
The impact of those toxic elements on the fish are very wide. Among them we can note the following:
o Reduce oxygen in blood
o Attack:
 Liver
 Retina
o Strange behaviour (swim on the side, gasping behaviour)
o Brown gills and blood
o Poor feed conversion
o Poor growth
o Fast swimming
o Fast breathing
o More disease
o Increased mucus production
o Darkening of body coloration
Seeing this long list of terrible effects we can understand the importance of keeping ammonia and nitrite low for the fish welfare!
One of the solution to avoid ammonia and nitrite is to have a very well adapted biological “filtration”. I mean a nice population of bacteria able to transform those toxic elements in nitrate. The trick is therefore to keep a low density of fish compared to the population of bacteria (exact ratio available in the free aquaponics training).
Plants are still in need of nitrate which is their main nutrient so you still need a certain quantity of fish in your ecosystem
Most fish species will accept 0.5ppm of ammonia or nitrite for a limited period of time but they will appreciate and live more comfortably a concentration between 0 and 0.2ppm.
I recommend beginners to test the water once a week and to monitor ammonia and nitrite. If a pick is detected please stop feeding your fish, renew some water and during the following days decrease the fish biomass by fishing a few fish.


Welcome here! If you are new, you will probably be interested to discover Jonathan’s six steps to build and manage an Aquaponics system. Click here to access for free! Thanks and good reading 🙂

If you can’t watch the video, here is the transcription:

Let’s talk nitrites and ammonia. What are they, how to balance them, are they dangerous for your fish? This is what we’re going to see together in this video.


A few weeks ago, I made a video about nitrates in aquaponics. Nitrates are very interesting because they are the link between the fish poo and the nutrient for the plants. So they are actually the nutrient for the plant.


Today, I would like to talk about nitrites and ammonia because they are the first particles that are going to be formed from the fish poo. Those particles can be very toxic for the fish. If they remain in the system and if you don’t have any good filtration, if you can’t really basically transform them into nitrate, then they’re going to build up in the system and they’re going to become toxic for the fish.


So the symptoms for the fish, first they’re going to start to be stressed. The fish are going to be stressed. They’re going to come to the surface. They’re going to swim strangely. You’re going to find some fish that are going to start to try to breathe the oxygen outside of the water simply because basically, their blood is not able to transport the oxygen efficiently.


It can also attack the liver and the retina, the eye of the fish. So it’s quite serious. Sometimes you will also find some fish with brown gills. You know, the gills they are brown or red, red-brown you know. That’s a sign that you may have high nitrite or ammonia in your water.


Same as for the nitrate, the fish are going to be stressed and here, way more, right? You don’t need a lot of nitrite and ammonia in the water to have a big stress on your fish.


So then the coloration of the fish can be darker so they can also be very quiet in the bottom of the tank. There are a lot of different behaviors that the fish can have that are linked to a high concentration of nitrite and ammonia. So you understand that we are talking about very serious injuries for your fish, and obviously, if you have way too much nitrite or ammonia, the fish can simply die.


So think of the welfare of your fish. Think of the health of your fish, and please keep those parameters low in your aquaponics system. So in the aquaponics system, we want obviously to generate a bit of ammonia and nitrites simply because they’re going to be transformed in nitrate. But in a normal aquaponics system that is well managed, you can’t really detect them.


As soon as they appear basically, they are transformed, thanks to some bacteria into some nitrate. So the ammonia and nitrites are disappearing straightaway. So the ammonia and the nitrite are part of the nitrogen cycle. You know, the fish poo in the water and then you got some ammonia that is released in the water, and we need this ammonia because then it’s going to be transformed into nitrite and then into nitrate. Obviously, the nitrates are the food for the plants. So that’s good. We want to have this mechanism, but the thing is that we don’t want the ammonia to stay ammonia. We don’t want the nitrite to remain nitrite. We want them to be transformed straightaway into nitrate.


So in your aquaponics system, when you check the quality of the water, you shouldn’t be able to detect ammonia or nitrite. And if you are able to detect them, it should be at very low concentration.


So what are the accepted ammonia and nitrite concentration? We are talking about 0.1 ppm, 0.05 ppm and it will start to be very harmful after 0.5 ppm. So then same as for the nitrates, every single species of fish has got different limits, and some fish such as carps are going to be able to accept a bit more ammonia and nitrite in the water than other fish such as trout.


So if you are raising carp, you should still aim to have a low concentration of nitrite and ammonia, but if you make a few mistakes here and there, you may be able to keep your fish surviving, while if you are raising trout, as soon as you make a mistake in the management of your system and you have too much ammonia or nitrite, the fish are simply going to die.


I think a good rule for all species is to keep the ammonia and nitrite level below 0.2 ppm. So now you’re going to ask me how to balance, how to make sure we keep our concentration below this maximum level. The best thing to do is to respect the ratio. You know you have a ratio of maximum fish biomass that you can keep in your system, and it’s related to the quantity of bacteria that you have in your aquaponics system.


So if you are in a grow-bed aquaponics system basically, it’s going to be linked to the volume of your grow-bed and the quality of the media. So in the free training that I offer in the description of this video, or in the corner you’re going to find an ‘i’ like information, if you click on the ‘i’ you will have access to this free training. It’s a step-by-step process where basically, I give you all the knowledge that you need to be able to build a good aquaponics system that is going to work, but I also give you some very specific limits and ratio that you need to respect if you build your own system. So the ratio is quite simple. We are talking about volume of fish tank per volume of grow-bed. Those type of things are very, very, very important. You need to keep them in mind.


If you respect those limits and ratio, in the design of your system, but also in the quantity of fish that you keep, then you always are going to remain underneath the 0.2 ppm of ammonia or nitrite.


If you go over, then it’s going to be a threat. So I don’t recommend to go over the limit that we fix in this free training.


So I hope this gives you a bit of information. Obviously, I don’t spend too much time talking about those two parameters. There are a lot of things we could say, but if you have any specific question, please ask it in the comment of the video, and I will be very happy to respond to your questions. And if you have specific knowledge to add on top of this video, please also add it in the comment. It’s going to be very useful for all the beginners who are starting aquaponics. So I really hope you enjoyed those videos. If you are new here, you can subscribe to the channel. I release one video every week, and I give some tips to help everyone to raise and to grow some food in his own backyard, thanks to aquaponics.


I’ll see you in the next video and bye-bye.


Don’t forget to get your free gift from this screen. You can also leave me a comment below the video. Subscribe to the channel and see my last video. I really hope to see you soon, and I wish you a fantastic success with aquaponics. Have a good crop!