President Reagan may leave the hospital for the White House this weekend, Dr. Dennis O'Leary of George Washington University Hospital said yesterday.

The president had a fever Tuesday night, the White House press office reported, but his temperature was close to normal yesterday and chest X-rays show "significant clearing" of the dried blood and damaged tissue in his left lung, struck by a .22-cal. bullet in an assassination attempt March 30.

The debris in Reagan's lung is now "barely perceptible," the report added.

Reagan also was reported walking with increasing vigor, and holding animated conversations with his doctors and visitors.

White House sources said a decision will be made soon on whether Reagan will make a previously scheduled trip to Mexico and California beginning April 23. They said the president has told his daughter Maureen that he will be in Los Angeles for her April 24 wedding and that he wants badly to make the trip.

Reagan signed an executive order yesterday establishing the Presidential Federalism Advisory Committee to study relationships between local, state and federal government.

"Unfortunately, our decentralized system of government has over the years been bent out of shape," Reagan said in a statement released by the White House.

The president's close friend, Sen. Paul Laxalt (R-Nev.), will chair the commission. "Of course, this is a matter Ronald Reagan and Paul Laxalt have discussed, lo, these many years," Laxalt told reporters. He shares Reagan's conviction that the federal government has taken over too many roles, and should return some responsibilities to local and state governments.

Laxalt defended makeup of the commission, which is heavily Republican and does not include many representatives from the Northeast. "I think it's apparently weighted," Laxalt said. After all, he added, the Republicans did win the election Nov. 4.

He said the commission would try to complete work by the end of 1982 and would use staff from the White House and Capitol Hill, but would not create a bureaucracy of its own.

Laxalt, who visited Reagan for about 15 minutes yesterday, said the president did not express worry about the fate of his economic package in the House. "I rather think that the bulk of his package will be approved by the House," Laxalt predicted.

Reagan also signed a proclamation in his hospital room making April 19 the beginning of Victims Rights Week.

"Only victims truly know the trauma crime can produce. They have lived it and will not soon forget it," the president, who was so recently the target of an assassination attempt, said.

White House press secretary James S. Brady was reported making satisfactory progress yesterday recovering from the bullet that entered his brain. A scan found "no evidence of complications," a medical report issued by the White House press office said. Brady napped much of Tuesday, but sat up in a chair for dinner, it added.

One goldfish, a 55-pound glass pig filled with jelly beans, assorted other packages of the president's favorite candy and 74,600 letters, telegrams and get-well cards have been received at the White House since Reagan was wounded, deputy press secretary Karna Small said.

The goldfish arrived in a water-filled plastic bag inside a box, and was sent by a 10-year-old boy who lives in Albany, N.Y., Small said. "I hope you get better and to help you get better here is a companion, a goldfish named Ronald Reagan II," Barnaby Dexter Bullard wrote the president.

He added a request: "If he dies, call this number" -- and he wrote his telephone number. The goldfish is swimming in a glass jar that formerly held jelly beans.

Reagan was visited by his wife, Nancy, son Michael and former Texas governor John B. Connally. Mrs. Reagan brought a large box of chocolates sent by the king of Morocco and a framed picture of Bob Hope, a friend of the Reagans, dressed in an Easter bunny suit.