You hear a lot nowadays about "pet therapy," which is not therapy for pets (who are almost past help once they acquire human masters) but is therapy for humans.

It has come as a surprise to some people that a dog or cat or canary or some such creature has been the blue-eyed salvation of some person or other who had previously seemed unreachable by any other means.

It is no surprise to me. It is no surprise to anybody else with an intelligence quotient over 84.

But I do think it interesting that carp, of all animals, have been able to achieve miracles comparable to those of Lourdes, and I suspect the reason is the same in both cases: the invalid has for a change been given some reason to hope, and never mind if the hope is itself irrational. It is important, first of all, for the invalid to find something outside his own misery to engage his mind. This is, needless to say, the force behind all art, all health.

Now as you doubtless know, the Japanese are very interested in carp, especially the ornamental kinds called Nishikigoi. My own view is that readers are a lot more interested in colored carp than editors think they are, but no point arguing the matter here, and I shall therefore refrain from a history of the colored Nishikoi carp from ancient times to the present, beyond saying that the center of their development has been in Niigata and the gorgeous color patterns we all know in carp today have come about largely in the last century.

A leading magazine about these carp is Rinko, which has an avid readership throughout Japan, where these carp fulfill roughly the same social function (only better) that golfing and horse racing fill in our society. Fine carp sell at racehorse prices; lesser specimens ornament fish pools in ordinary private gardens, and the least gorgeous carp wind up in restaurants. More than $100 million of these ornamental carp are sold in Japan each year.

In an effort to share enlightenment, the editors of Rinko put out an English edition which has fine things in it, including moving testimonials about how a certain carp did not clarify the color patterns and how Mr. So-and-So had faith in the fish and finally succeeded in getting the colors clarified and produced a great champion carp.

Ryo Kamiya, for example, fell in love with a certain koi (as we call the Nishikigoi) even though Mr. Isa, a great authority, held little hopes for its championship potential. Kamiya persisted, however, for he saw in this carp what nobody else did.

"Dr. Miki Kan and Mr. Shozaburo Sato affirmed that this carp's hi would never be clarified. Indeed so."

The years passed. Kamiya boarded out his carp in the fine green-water pools of this carp specialist and that.

Higuchi suggested the fine mud pond of Sueki. No dice. Then Ogawa tried it in his fine pond. No dice.

Finally, Kamiya kept the carp in his own pond, and there the colors clarified. His faith in this carp was justified.

"See how it looks now," Kamiya crowed in one of my favorite issues of Rinko. (The fish had just won Best in All in Osaka).

"I admire myself because I refused to be tempted by foul-tongued people and instead I could put up with keeping it for a long time."

Winning in Osaka is rather like a double-crown of the Preakness and the Belmont. And all this glory came to a carp that nobody had any faith in except its doting owner, Mr. Kamiya.

Very well. In this case the carp did not actually cure anybody, of course. But does anybody doubt that the silver-haired Kamiya found in this fish new grounds for trusting his own faith and for trusting the providence that lies beyond us and surrounds us? Probably an old citizen of Japan is aware that life can sometimes be grim. Still, in his old age, against all odds, his carp won at Osaka.

Let us now move to a case in which a carp not merely exalted an old man's heart, but snatched an invalid woman from the very jaws of despondency and death:

Yuzuru Satake reported in Rinko that his sister, long bedridden, "thanks to Nishikigoi has miraculously recovered from her illness, and that she may be able to rise to her feet by herself."

This lady was born in 1907 and "went through a major operation on her internal organs including the stomach for some six hours."

"Since 1967 she has been bedridden, and she eats only one third of ordinary people; she needs others' help even when she falls down from the bed of only 10 centimeters."

Fortunately, her brother thought some beautiful carp might give her a new cheerfulness with which to endure her afflictions, and saw to it that a carp pool was built only a yard away from her bed, outside her ground-floor sickroom.

"The koi were so tame that they gathered at the feeding place as soon they heard the sound of opening windows, in only two weeks. When the patient clapped her hands, the koi approached to her to beg for food. It is no one but the patient herself that felt really glad . . . In three months only, she became able to creep around the room by herself. It is probable that she may walk in six months more. It is really incredible.

"It goes without saying that the family of the patient, full of despair, has changed into a bright home and that the koi have become their mascots.

"Koi has a longest history among fishes of being kept by men and it soon gets close to its keeper. Above all, I think it obediently accepts our love. As soon as koi hear the sound of clapping hands, they come close to the people and look at them, or they suck our fingers which are very cute gestures.

"We never get tired of looking at them. There are a number of enjoyment through koi keeping, so I trust koi are good companions for human beings, especially for long-suffered patients. I sincerely wish this sort of affairs would happen more often."

I quote these few words partly to show how enchanting English is when the speaker is sincere, and never mind the grammar, and also to point out that little fragment in which the carp "accept our love," because health cannot be maintained except by the acceptance of what we can offer. The wise and therapeutic carp accept the love and the patient gets well.

There is more philosophy of health there than you will find in some doctors, though most doctors who have snatched patients back from the grave have tremendous emotional reservoirs. Technicians are all very well, and the best doctors are superb technicians, but cheating death requires heroic measures. Sometimes a carp, and often a dog, will do it.

It is stupid that hospitals bar dogs. A good hound is worth half a nurse or two surgeons. But hospitals, I imagine, are developing enough critics without my own sour reflections on them.

All this superstructure. Sometimes costly techniques save lives, no doubt of that. But sometimes a dog would do. A carp, even.