All-Male fry without intervention

Uniform batches

High male ratio (>99%!)

Sustainable for fish, employee and ecosystem

Well developed immune system; stronger fingerlings

YY-Technology explained

1. YY-development

Since 1996 Til-Aqua International has been working on the development of YY-males and YY-females in tilapia for the production of all-male tilapia without the use of hormones; Natural Male Tilapia (NMT™).

2. Manual selection – YY line

In 2000, when the Til-Aqua YY line was obtained, manual selection for 100% male offspring was initiated. Each and every male and female from the YY line were crossed with respectively an XX-female or an XY-male. Only those fish that produced 100% male offspring in these crosses were kept for the Til-Aqua genetics program. This selection resulted in today’s male ratio:

> 99%* !!

 * Under optimal exogenous conditions

3. Family selection – female lines

The various Til-Aqua female lines originate from two strains; Egypt and Philippine (gene pool Gift, Citralada, and more).

For improving these female lines, family selection is applied  to improve growth performance and physical appearance.

4. Heterosis

The Til-Aqua YY line and the Til-Aqua female line have been completely separated from each other since the beginning. This avoids inbreeding on the NMT™ offspring and also causes a so-called heterosis effect, meaning the offspring is performing better than the average of its two parents: 

1 + 1 > 2 !!

5. Other female lines

Since 2016 Til-Aqua International is testing the performance of Natural Male Tilapia offspring that is originating from breeding Til-Aqua YY males with other commercially available female lines. This has given excellent results:

Til-Aqua NMT 

99% ♂ – Uniform and excellent growth

Egyptian NMT 

97% ♂ – Uniform growth

Phillipine NMT 

96% ♂ – Excellent growth

Kenian NMT 

96% ♂ – Performing well under cold conditions


98% ♂  – Excellent growth