Hi
In answer to your question it can be done but the results may not be as vibrant as you would like.
Many brown tattoos against darker pigment skin tend to look a little faded or can seem to be scar-like in some cases.
If you use a black outline and and black n grey shade the natural colour of your skin will fill in much of the colour of the turtle.
For your skin type you would need colours like deep red, purples or dark blues to show up well against the skin.
Speak with a pro artist who has experience in your skin type (not just any artist who will say yes because they want the money).
Take Care
Matthew