This is an Orange and Black Oranda Goldfish.

Goldfish - My new black Comets (:
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For many years, it was believed that goldfish had originated from the Crucian Carp described by Linnaeus in 1758. This fish has a wide range across the waters of the European continent, running west to east from England to Russia, north to Scandinavian countries in the Arctic Circle and as far south as the central France and the Black Sea. However, recent genetic research points to as a more likely ancestor.
black comet goldfish | Goldfish - Black Comet (probably a Koimet)
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Goldfish are a common pet for children and an ideal starter fish for those interested in having a home aquarium. They come in a variety of colors, including white, silver, orange and black. Goldfish can be all one color or have random patches all over their bodies, including their fins. These colors may change over the lifetime of the fish. black comet goldfish | Black Comet Goldfish Veiltail Black Comet
Photo provided by FlickrGoldfish - Black Comet (probably a koi/comet hybrid)
Photo provided by Flickrblack comet goldfish | Mirror-scale goldfish
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*Awarded Answer
: You need to be careful when choosing to keep other fish with your black moor because they are a lot slower swimmers than other goldfish. If you keep some of the faster swimming species like the comet goldfish or a koi fish they will EAT ALL THE FOOD. That will leave no food for your slow fish. Choose a fish that will share the same swimming traits as your blackmoor. Other fancy goldfish work great. There are lots of different species so just take a look at how fast they swim and relate it to your fish.Here is a goldfish to go along with the tank I pinned earlier. I am hoping to get a 20 long and a black moor goldfish Gold fish "Calico". photo by Osamu Yamazaki.Red & black oranda--with eyebrows! next time i keep fancy goldfish i'm going to do a 90 gallon instead of a 60 and i'm going to buy a HUMONGOUS canister filter (instead of two giant wet/dry box filters) because these little cherubs really trash the water.
Take the advice on a larger tank because it is true. That next step up is pretty similar in size to the 10 gallon anyhow. It will be fine for the baby Blackmoor but once he grows more… Get another fish that swims slow in the goldfish family. I’m trying to think of that other fish that has a plump belly and is very round. I want to say its the Ryukin species but maybe I’m wrong.
Your especially not going to be able to have two fish in a 10 gallon for sure. I would start looking around for a 20 gallon at bare minimum. For two full size goldfish, a 30 gal aquarium is the safe route to go. But as far as a tank mate or friend.. I would throw a bottom feeder in there to help eat some of the algae with another type of goldfish or koi. They are closely related though the Koi fish is a faster swimmer so you would have to make sure the Blackmoor was getting enough food even with him being goldfish. So beautiful. And just to be clear, it is NOT a beta! Ok? For all you people out there who might mistake this fish for a beta its a black goldfish. Thank you for your time.(: