Maryland Code, Natural Resources § 4-11A-21

(a) A person may apply in writing to the Department for a permit to breed, propagate, and sell any species of game and freshwater fish protected by law, in ponds or lakes which he owns or leases. The Department, upon receipt of a permit fee of $5 may issue to the applicant a breeder's license permitting him to hatch, rear, transport, sell, barter or exchange any fish. A fish breeder's permit expires on December 31 following the date of issuance.

(b) The Department shall promulgate regulations governing the release, possession, sale, shipment, and identification of every game and freshwater fish bred under a fish breeder's permit. The Department may require any report necessary concerning the operation of a fish breeder's permit. Any permit issued under the provisions of this section may be revoked for a violation of any provision of this section or any regulation made pursuant to it.