Appellant Juan Pequeño (“Pequeño”) appeals, pro se, the district court’s denial of his appeal from a Bankruptcy Court Order Denying Debtor’s Motion to Deny Administrative and/or Recovery Fees. Appellee Michael Schmidt (“Schmidt”) is Pequeño’s Chapter 7 Trustee.

We have previously addressed this case in several opinions, which collectively lay out the facts and posture below. 1 We resolved the issue at hand in In re Pequeño, 240 Fed.Appx. 634 (5th Cir. 2007), in which we affirmed the district court’s dismissal of several of Pequeño’s claims, including his appeal of the bankruptcy court’s Compensation Orders approving Trustee counsels’ compensation. The district court dismissed those appeals for want of prosecution, as Pequeño had failed to file timely briefs. See id. at 635. Pequeño’s claim is barred by res judicata. A dismissal for failure to prosecute bars any further adjudication, because it operates as an adjudication on the merits. Nielsen v. United States, 976 F.2d 951, 957 (5th Cir. 1992). We therefore AFFIRM the judgment of the district court. We also note that Pequeño has appeared before this court six times in this matter; at least four of the appeals — including this one — have been frivolous. Pequeño is warned that future frivolous filings will subject him to sanctions.