Is there such thing as a Nova Goldfish?

It's possible you've misheard or seen a misspelling. There are many varieties of goldfish, and some have similar names, such as:

* Oranda Goldfish: These goldfish have a distinctive "hood" or "cap" on their head.

* Comet Goldfish: Long, flowing tails are a characteristic of Comet Goldfish.

* Fantail Goldfish: Fantails have a broad, fan-shaped tail.

If you can provide more information about where you encountered the term "Nova Goldfish," I might be able to help you identify the specific goldfish you're thinking of.