Well i remember when i replied to a thread exactly like this.
It wasnt pretty that was when i was a bit younger and a little more ignorant and it turned into an argument. Also there is no correct pronunciation IMO! so say it how you like! No one cares and/ or is going to go to your house and threaten you to say it how they want you to or the correct way lol!!
Go to this link, http://www.google.com/search?source=...AAAqgQFT9AnMFw
because when i typed in "BETA FISH" IT says did you mean "Betta fish"