I think you just had normals that looked really pale and unhealthy; just as you thought.When I had a spawning pair of managuense, there would usually be 3 or 4 individuals out of each spawn that would basically be this color.
I would cull them and used them as feeders, I found the pale color made them look like some kind of generic unrecognizable species, but to each their own.
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The thread I posted the link to was from here in the US the fish originally came from Here in Jersey and went to an MFK member VRWC. I don't know what ever came of that fish.