Do all yellow lab have back on top fin?

[CraigMac]

Bought 8 yellow labs when I first set up my 90 gallon tank. Well as they've grown I've noticed 6 of them have black on their top fins and varying amounts of black on other fins. However, the other 2 have zero black, they are just all yellow. Also, these 2 seem to be a bit smaller then the others.

So, is this just variables within labs or could I have 2 impostors in the group?

 

[Ovid]

Some have the black in their pectoral and dorsal fins and some don't. There are stripeless and also those with an absence of black (a type of albino where stripes appear white).

 

[Jjordan16]

Only some of mine had black on their fins, it was about 50/50

 

[kay-bee19]

A naturally occuring solid-colored labidochromis caeruleus morph (or variant) is found at one site on the eastern shore of Lake Malawi (the Tanzanian side) near Cape Kaiser. This all-white blue-hued morph, seldomly collected and exceptionally rare in the hobby, naturally lacks black fin markings.

The significantly more common (at least in the hobby) 'electric yellow' morphs are found on the western shore of the lake (the Malawi side) and are collected at Lion's Cove, Nkhata Bay, and nearby adjacent area's. These morph's range in color from yellow to white-blue hued and all have black fin markings.

There were efforts years ago (still ongoing?) to create solid-yellow 'yellow labs' which are derived by crossing yellow lab X red zebra hybrids back with yellow labs. In the hobby, solid "Yellow labs" lacking black fin markings very likely boast labidochromis caeruleus X metriaclima estherae lineage.

 

[CraigMac]

A naturally occuring solid-colored labidochromis caeruleus morph (or variant) is found at one site on the eastern shore of Lake Malawi (the Tanzanian side) near Cape Kaiser. This all-white blue-hued morph, seldomly collected and exceptionally rare in the hobby, naturally lacks black fin markings.

The significantly more common (at least in the hobby) 'electric yellow' morphs are found on the western shore of the lake (the Malawi side) and are collected at Lion's Cove, Nkhata Bay, and nearby adjacent area's. These morph's range in color from yellow to white-blue hued and all have black fin markings.

There were efforts years ago (still ongoing?) to create solid-yellow 'yellow labs' which are derived by crossing yellow lab X red zebra hybrids back with yellow labs. In the hobby, solid "Yellow labs" lacking black fin markings very likely boast labidochromis caeruleus X metriaclima estherae lineage.

Interesting. Thanks for the insight.