Midas getting black "areas"??

[Gebo]

4 inch midas. At first his lips and nose got a little black. Sort of like he had been in a boxing match. He and Mr. Pike were doing a little "mouth-to-mouth." But I just noticed today that the tips of this tail and the very tips of his bottom pointed fins have turned "black" also. What's the deal?

[rus]

midas go through several color changes before they reach adulthood. this is normal.