I have had this very fin form develop in a breeding female and 1/2 the fry developed the same fins. An outcross corrected the problem thru selectively breeding a healthy fry of the deformed female to a completely different stock of FM's. I have yet to see it return. The genetic defect is still there but is currently suppressed.
When line breeding siblings many different dominant traits will override the recessive traits. The grow out of the fry tell the story in each case and the next breeding parents are the corrective actions. Once corrected breed the youngest fish back to a healthy grandparent to fix the strain, be it a color change or fin trait. This will make future generations breed true to that trait.
HTH, Rich
When line breeding siblings many different dominant traits will override the recessive traits. The grow out of the fry tell the story in each case and the next breeding parents are the corrective actions. Once corrected breed the youngest fish back to a healthy grandparent to fix the strain, be it a color change or fin trait. This will make future generations breed true to that trait.
HTH, Rich