[HAYNES AND BOONE LETTERHEAD APPEARS HERE]
 
                                                                     EXHIBIT 8.1

April 8, 1996



Coda Energy, Inc.
Diamond Energy Operating Company
Taurus Energy Corp.
Electra Resources, Inc.
5735 Pineland Drive
Suite 300
Dallas, Texas 75231

Re:  Offer by Coda Energy, Inc., Diamond Energy Operating Company, Taurus Energy
     Corp. and Electra Resources, Inc. to exchange 10 1/2% Series B Senior
     Subordinated Notes due 2006 and the Guarantees thereof for any and all of
     10 1/2% Series A Senior Subordinated Note Due 2006 and the Guarantees
     thereof


Ladies and Gentlemen:

We have acted as special counsel to Coda Energy, Inc. (the "COMPANY") and its
subsidiaires, Diamond Energy Operating Company, Taurus Energy Corp. and Electra
Resources, Inc. (the "GUARANTORS"), in connection with the offer (the "EXCHANGE
OFFER") to exchange the 10 1/2% Series B Senior Subordinated Notes Due 2006 and
the Guarantees thereof (the "EXCHANGE NOTES") for any and all outstanding 
10 1/2% Series A Senior Subordinated Notes Due 2006 and the Guarantees thereof 
(the "PRIVATE NOTES").

You have requested our opinion as to certain United States federal income tax
consequences of the Exchange Offer.  In preparing our opinion, we have reviewed
and relied upon the Company's Registration Statement on Form S-4, filed with the
Securities and Exchange Commission on April 8, 1996 (the "REGISTRATION
STATEMENT"), and such other documents as we deemed necessary.

On the basis of the foregoing, it is our opinion that the exchange of the
Private Notes for Exchange Notes pursuant to the Exchange Offer will not be
treated as an "exchange" for United States federal income tax purposes and
therefore, is not a taxable transaction for such purposes.

The opinion set forth above is based upon the applicable provisions of the
Internal Revenue Code of 1986, as amended, the Treasury Regulations promulgated
or proposed thereunder, current positions of the Internal Revenue Service (the
"IRS") contained in published revenue rulings, revenue procedures, and
announcements, 

 
Coda Energy, Inc.
Diamond Energy Operating Company
Taurus Energy Corp.
Electra Resources, Inc.
April 8, 1996
Page 2

existing judicial decisions, and other applicable authorities. No tax rulings
have been or will be sought from the IRS with respect to any of the matters
discussed herein. Unlike a ruling from the IRS, opinions of counsel are not
binding on the IRS. Hence, no assurance can be given that the opinion stated in
this letter will not be successfully challenged by the IRS. We express no
opinion concerning any United States federal income tax consequences of the
Exchange Offer except as expressly set forth above.

We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm and the summarization
of this opinion under the section titled "Certain Federal Income Tax
Considerations" in the Registration Statement.

Very truly yours,

/s/ HAYNES AND BOONE

Haynes and Boone, LLP