I have a 10-gallon freshwater tank with 3 fishies in it, two rasbora hets and one platy (don't know the common name of this particular species...), maybe not the most ideal fish combination to share the same tank, but that's just how it worked out, long story. Anyway, the platy guy is all orage with black fins and tail, and some black spots on his back, a noticeable patch. A couple times now I looked at him and saw that all of his spots were gone! Completely gone, he was just an orange fishy with black tail and fins. So, I'm curious, first of all, if this is normal, and if so, why does it happen?

He seems to be acting normally, although often he hides in a rock cave and sits there, but more frequently he is swimming around the tank just fine.

Thank you!

i'd say its a sign of slight stress, my small blue three spot gourami loses its spots when shesstressed, then i got mroe fish to dilute the pecking order more, and now shes happy and healthy, i'd say get a few more platys, like 3 more, try to have 1 male and 3 females, and ur platy should be fine.

Hmmm.... I would first have to ask how old is the platty?