The two fish are the Mummy Fish and the Bride of Frankenstein. Both are available to purchase with coins, rather than premium currency, but in terms of affordability, the Bride of Frankenstein is much more suited to those players on a budget, as she costs just 1500 coins to the Mummy Fish's 8500 coin price tag.
Also, while the Mummy FIsh can be customized to your gender preferences, the Bride of Frankenstein has to remain a female fish. However, both can be renamed and both grow to adulthood in 32 hours flat.
For those who take time to think about their purchases, know that the Mummy Fish is specifically listed as only be available until Halloween, and we're assuming the same goes for the Bride of Frankenstein, although she isn't actually marked as such. Either way, you'll want to add these fish to your tank quickly to have time to celebrate with them, so shop fast!
Check out the rest of our Halloween 2010 coverage right here.
Will you purchase either of these fish for your tank? Sound off in the comments.