First, as a technical matter, no. The duty to state fees or provide a contract is not a fiduciary duty. He's still bound to comply with the relevant ethical duties, which can be found here: http://www.floridabar.org/divexe/rrtfb.nsf/FV/A8644F215162F9DE85257164004C0429. A quick and dirty reading of them indicates that charging a 40% contingent fee without a contract or abrogating a specific advertised arrangement (e..g, "free initial consultation") could violate that ethical duty.
Second, as a strategic matter, it may be a good idea to advise your attorney that you are considering filing an ethics complaint (and leaving negative reviews on any reviewing website). If your attorney is clearly in the wrong, he may be incentivized to do the right thing when confronted with the threat of a damaging complaint.
Third, keep in mind that actually suing your lawyer has consequences for the attorney-client relationship generally, and attorney-client privilege and the duty of confidentiality in particular. For the precise consequences regarding those, if #2 above doesn't work, contact an attorney... and get the fee agreement in writing.
I am not your attorney. This is not legal advice. Do not rely on my statements for any purpose whatsoever. I may not even be *an* attorney in your state. Go hire an attorney.
As a general response, most Bar Associations (including Florida) offer a free Legal Fee Arbitration Program. I believe both parties have to agree to participate, but this may be a cheaper and faster alternative to litigating, and many attorneys prefer to participate as public lawsuits over fees can be bad for business. I don't believe (but you should check) participating in the program would preclude filing a separate Bar ethics complaint (if warranted).
I'm a lawyer, but I'm not your lawyer unless we sign an agreement. While my practice involves a wide array of national and international issues, I am licensed only in Louisiana- where the legal system can be unique. The brief informational response provided here is not a substitute for legal advice, and you may need to act promptly to preserve your rights.