Frequently Asked Questions:

Why is it preferable to raise only males in commercial production and in aquaponic systems?

Males grow much faster than females, have greater size uniformity and have a lower food conversion ratio.  Tilapia breed very heavily.  The males will spend time with courting rituals rather than growth, and become aggressive fighting over females.  Fry and fingerlings can get stuck in the pipes of a RAS and clog the system.  Raising only males eliminates population control issues and wasting expensive feed on slower growing females and there is no need to wait to hand sex your fish until they reach 3-4 months old.

What is sex reversal?

Fish are special animals.  They can sex reverse at any time during their lives naturally.  Some fish species change sex when they reach breeding age.

Tilapia can be made to be either female or male during the first 3 weeks of life.  This can be done with the use of hormones or temperature.   Methyl testosterone or YY technology to create all male populations have been the method of choice.

Can fish be inbred?  Aren't they just fish?

Genetics is an important factor with fish as well.  When you are looking for fish to stock your system you will want to make sure your fish are of the highest genetic quality.  Many sources do not have a genetics program and are breeding brothers and sisters.

Inbreeding leads to genetic problems, poor growth, a variety of health problems and abnormalities. 

Noa Fisheries is a commercial hatchery with a strong genetics program.  The fish are graded a culled at regular intervals to ensure that the end product is of the highest quality with the fastest growth and free of disease.

How many fish should I put into my tank?

There is not a simple answer to this question.  The amount of fish you want to stock depends on how much time you can devote to maintain a healthy environment for your fish.  The more fish you put into your system, the more solids.  If you wish to densely stock you will need to have efficient solids removal, aeration, and bio-filtration.  You will need to have a back up system in case of power loss for the DO levels.  A commercial system is stocked very densely at approximately 1/2 lb fish per gallon or 227 g per 4 L.    This is obviously not an ideal stocking rate for a beginner or someone with very little time to monitor and maintain their system.  A new system should be cycled before fish are added.

What size tank do I need?

If you are ordering small fingerlings or a small amount of large fingerlings you can start with a properly cycled 10 gallon or 40L.  But, you will have to move the fish to a larger tank to allow room for your fish to grow.  Tilapia grow very quickly, you will need to have a plan in place for a larger tank to allow for growth.

Can I put tilapia with other species together in the same tank?

Fish should be kept as close to the same size as possible to prevent bullying.  Other fish species carry different diseases than tilapia which may be dormant.   We do not recommend mixing tilapia with other fish species, especially feeder goldfish. Feeder goldfish are not meant to live very long and often carry disease.   Pond fish can also carry disease and may contain parasites.   If you wish to add other species ensure they are treated with salt before placing into your system or mixing with tilapia.

Whatever combination you decide to add to your tank is completely at your own risk.

Can you ship different strains together?

Yes, we can ship together different strains in one shipment but not in the same bag.  Shipping is extremely stressful to the fish.  Each fish has their own personality and they must be shipped with their own strain.  Each bag is filled with pure oxygen. If we are shipping two different strains the double insulated box needs to be large enough to accommodate two bags and the same amount of oxygen in each bag.  Shipping two strains therefore costs more than shipping one large order of one strain because a large factor of the shipping price is determined by the size of the box.

What are the growth rates of each fish?

This is not a simple question. Growth rate depends on many factors:

Water quality

Water temperature

Dissolved O2

Feeding rate

Quality of feed

Size of tank

If all of the ideal  conditions are met, nile tilapia grow at a very fast rate and are machines at converting food into growth. With ideal conditions they can expect to reach fillet size 750g in 6-8mos.  It really depends on many environmental factors.

How often should I feed my fish?

Tilapia are fed at different rates depending on the size/age.

It is best to contact your feed company and ask them what is their recommended feeding rate.  You will need to know the approximate total weight of your fish and then you can calculate the amount of feed you will need to administer over the course of a day.

Many facilities hand feed their fish to avoid wasting expensive feed.  Tilapia are a warm water fish. Temperature is a very important factor for the fish to be able to metabolize feed.  Tilapia prefer 28C-30C for optimum growth.

If you have a hobby system, feed your fish 3-5 times per day as much as they will completely consume in 15 minutes.  Keep an eye on the temperature of your system.  If the temperature drops below 18C tilapia will stop eating.

What size pellets should I feed my fish?

Feed size Fish Weight   Fish Size
Fry powder/starter <0.2g <1" (25mm)
#1 Crumble 0.2-1.5g 1-2" (25-50mm)
#2 Crumble 1.5g-5g 2-3" (50-76mm)
1mm pellet 3-9g 2.5-3.5" (63-89mm)
1.5mm pellet 5-12g 3-4"  (76-102mm)
2.0mm pellet 12-23g 4-5"  (102-127mm)
3mm pellet 30-40g 5-6"  (127-152mm)
5mm pellet 90-250g 8"+ (203mm+) 


*note these are the recommended sizes for salmon/trout.  Tilapia has a larger mouth opening and can accept larger pellets at a younger age/size.

For a hobbyist, such a variety of pellet sizes is not necessary.  For fry we supply enough fry starter to go to #2 crumble.  You only need 1mm pellet, 3mm pellet and then 5mm pellet, which are are the standard sizes for koi feed which is readily available at your local pond/aquarium retailer.

What is the market size for tilapia?

Tilapia are most commonly grown for the fillet and live market.  The Asian market prefers 750g/1.5 lbs.   Some ethnic markets that cook the fish whole prefer 600g. There are niche markets for larger or smaller size tilapia.