Silver dollars changing colors?

[Sambo7475]

I added a couple of younger spotted silver dollars a few weeks ago. These guys are less skittish than my older two, and chase each other all over the tank. No fun nipping, it's almost like a mating ritual, but I have no experience with this species' mating behaviors. Their anal fins turn black, and they get orange spots behind the gill plates as well as on their pectoral fins. I've never seen the orangish display on any silver dollars before. Has anyone else? Not concerned, just curious.


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[Sambo7475]

Here are couple of pics along with one of Fatone, my older fella


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[Fresh2o]

Is it possible that the newer ones are a different species of Metynnis?
These appear to be available: Metynnis argenteus, Metynnis hypsauchen, and Metynnis maculatus
I had some years ago and they looked like your (argenteus?). The smaller ones look more like maculatus.


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[Sambo7475]

I think you might be right, I never knew there were so many different species. The youngsters appear to be M.maculatus, Fatone is definitely M.argenteus, the other spotted might be M.lippincottianus?
I learn something new in this hobby all the time ?. Thank you!


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[Fresh2o]

You're welcome and it appears you've got quite the zoo of plant eaters in there. ???


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[Sambo7475]

That's quite true. All plastic in there now. Tried crypts, Java and one other plant as resistant to munching early on in this adventure. All were stripped to the roots within minutes. I do like the silver dollars, so allowances must be made . Thanks again for your help!