In aquaponics, fishes provide nutrients for plants to grow by bacteria breaking down ammonia from their waste into nitrates which is then used by the plants. Its essentially a closed-loop ecosystem created by the symbiotic relationship between plants and fishes.
Aquaponic Fishes can function with up to 18 hours of light to carry out their daily functions as living organisms. Light is a necessity for aquaponic fishes and helps contribute to their health, stress levels, and reproductive functions.
Fishes are the driving force of an aquaponic system; they provide the source of nutrients that plants use. Healthy fishes produce healthy nutrients.
And Healthy fishes are based on how well they thrive in their environment. The amount of light provided for the fishes can affect their health and how they function.
See our complete guide on aquaponics and what you need to know to run a successful system.
Do Fishes actually need light?
The fact that the eyes of common fishes like tilapia, perch, and koi are relatively large says much about their evolution. These fishes have these eye structures because they use it for survival in the wild.
Fishes need light to carry out their daily functions.
The conditions in an aquaponic system is not anything close to conditions these aquatic animals may be subjected to in the wild.
Fishes need light to see their food.
Housed in a closed environment with many other fishes, being able to see the food when its available is a part of survival in an aquaponic system for fishes.
Without light, the fishes would have a hard time finding food which in turn of left uneaten can lead to fouling of the system. Therefore, the more light fishes are exposed to tend to increase their growth rate since they are able to feed more with the available light.
The reproduction of fishes would fall drastically since fishes will not be able to carry out the function.
Have you ever seen the courting ritual of the male and female tilapias? They are very playful and territorial around this time. Without light, these attributes of reproduction would cease and the cycle itself would not occur.
How does light affect the Health of the fishes?
Light is required for body pigmentation especially during the early development of fishes. This is true for most fishes especially colorful fishes like kois and tetras.
High-intensity light can be stressful or even lethal to fish.
How much light does aquaponic fishes need?
Reproduction and spawning are best achieved with a photoperiod of 18h and 2500 Lux light intensity. Meaning that the fishes can perform well with a light period of 18 hours a day.
Source – https://www.scielo.br/scielo.php?pid=S0100-879X2004000400004&script=sci_arttext
Lux is the SI-derived unit of illuminance and is equal to one lumen per square meter.
What types of light are best for aquaponic fishes?
The type of light that fishes are subjected to are produced different outcomes when it comes to reproduction.
The species under speculation is the blue Nile tilapia because its the most commonly used fish in aquaponics due to its growth and reproduction rate.
Blue environmental color influences fish reproductive behavior. The higher reproductive rate and more intense nesting behavior in groups under blue light strongly suggest that this light stimulates reproduction in Nile tilapia.
Blue light comes mainly from light in the range of 5000k and 6000k, light intensity.
The light spectrum ranges from 1000k to 10000k where 1000k is the dimmest light and 10000k is the brightest.
From the same study listed above, it was concluded that fishes perform better and produce fewer stress hormones when subjected to living in a green environment.
I think mostly its from their nature and being surrounded by green plants calms their behavior since they have a more homey feeling.
Its only natural to feel at home if you are surrounded by the thing you are accustomed to.
Apparently, these fishes are no different and the benefits can be seen from their low-stress levels and reproductive responses when around these calming colors.
What Type of light Should you Use for Fishes?
LED lighting is the best kind of light that should be used for fish. LED or Light Emitting Diode is very efficient and most beneficial when compared to other light sources.
If you have to keep the light on for an 18 hour period the power consumption over time would certainly add up. LEDs are very energy-efficient and long-lasting.
Here is our pick from amazon for aquatic lighting. It’s really worth a look and the ratings for this light speak for themselves.
Apart from the power aspect, Other light sources can add unwanted heat to the aquaponic system which brings a lot of negative side effects such as decreases dissolved oxygen and pH swings.