Here the tail rays extend beyond the tail edge, producing a crown-like appearance. How much the rays may extend depends on the genetic makeup of the fish. The crowntail trait can be found in betas of any tail type and shape. For instance it can be seen in VT, D, SD, HM (CTHM = half-sun) and DT. The crowntail gene intermediary inherited. This means that crowntail carriers most of the time already show more or less extended rays beyond the tail edge.
Black copper CT male
Blue mask CT male
Multi cambodian halfsun male
Crowntail genetics
A normal singletail betta is represented by: CTCT
A crowntail betta is homozygous for the crowntail gene (CT) and is represented by: ctct
A singletail betta which is carrier for the crowntail gen is then represented by: CTct
Crowntail x normal
100% crowntail-geno (CTct)
Crowntail-geno x crowntail-geno 
25% crowntail (ctct)
50% crowntail-geno (CTct)
25% normal (CTCT)
Crowntail x crowntail
100% crowntail (ctct)
Crowntail-geno x crowntail
50% crowntail (ctct)
50% crowntail-geno (CTct)
- Joep. “Crowntail Genetics” www.Bettas4all, . Accessed – November 17 2013 <http://www.bettas4all.nl/viewtopic.php?f=28&t=128#.UokyiPmX9yU>