Yellow Lab Fins

A pure yellow lab will have a black dorsal stripe although the fish may keep it colored down so it is hard to see.

A fish without this stripe may be a hybrid.

Thanks DJRansome.

Should I wait for some time to for them to show the color or take them back & try and exchange them with other individuals?

If they're still small, it's somewhat common to not see any black yet. It'll come in.

Even when small you can usually see a hint (or outline)of where the black will be on the dorsal fin. Are you referring to that or the anal and pectoral(?) fins?

I am referring to the Dorsal fin.

3 or 4 have this black in their dorsal fins but a couple don't.

They all were bought at over half an inch size and are now 1 inch and over in size.

If they don't have it at all then they are not Labidochromis caeruleus.

Rice - those are a NICE strain to have so much black so early.

Mine all show at least some on their dorsal, and DJR is right - none = not pure YL. Should have at least a hint (look towards the front).