Pretty frog and goes nicely with the red
Another option for a darker container is a glass aquarium. This would work especially well for the 'above' shots if you have an open frame style of stand or can safely position it between two tables so the background of the floor is far away or otherwise not hit by your light. Or put a piece of black felt below it. Or whatever colour you'd like

. Reflections off the glass should be pretty minimal or non-existant with the lighting setup you have here. In the other angles it would be trickier to make this seamless though, you'd need to avoid having any edges of the tank visible so you might need a pretty big tank as that looks like a pretty big frog!
A d50! That's getting old in the tooth but the sensor is still a beauty and capable of great stuff and should be pretty darn cheap these days. Enjoy it!