Why is my Rainbow Shark black?

Question
Dear Karen,

I just got a rainbow shark. And what i was told is that when they have space they get colorful but mine is BLACK except his tail it turned red but the rest of him is black.

Be honest and be helpful ok.

Thanks.

Answer
Hi Ethan,
Sounds like you actually have a Red-tailed shark. These are gorgeous fish. With a velvety-black body and brilliant red-tail. The rest of the fins are black. Here's a picture-
http://www.aquariumlife.net/profile-images/redtail-shark.jpg


A lot of times rainbow sharks get mixed in the same tank as Red-tails at the petstore.

Best wishes and I hope this helps!
Karen~