S	DT
S	S,S	S,DT
DT	S,DT	DT,DT

Alleles		25% S,S, 25% DT,DT, 50% S,DT
Genotypes		50% Homozygous, 50% Heterozygous
Phenotypes		75% Single Tails, 25% Double Tails

Heterozygous Single Tail x Heterozygous Single Tail

Ok, so maybe that was too easy. Fine then smart guy, push back on your browser and take the quiz! Wait... before you do that one little question. Why can only single tails be heterozygous??

If you can answer that than you now truly understand Betta tail genetics. I now dub thee tail genetic god or goddess! Now go have fun fun breeding your Bettas!