The colorful Japanese carp down in the Commerce Department basement don't have a calendar in their pool, of course, but it's worse than that.

They missed the great festive Carp Season, which runs either from May 1 to May 10 or from May 10 to May 20, depending. Anyway, it's 10 days of May during which the carp from Yamakoshi to Yedo feel lust in their hearts and, by the end of the month, account for millions of new rainbows which delight and satisfy koi fanciers. By June, everyone knows, it should all be over, but it hasn't even begun.

In Japan 120 million are sold yearly, and while a distressing number wind up in restaurants, still many are bought for ornamental garden pools.

The ones in the basement at 14th and D Streets N.W. are part of the National Aquarium collection of notable fishes. Since the Japanese government gave them in 1972 they have lived in a shallow squeaky-clean pool, with labels to show you which is the Kohaku (red and white) and so on.

"What a pig," says their keeper as a happy one swims up to take canned corn from the outstretched hand. Some say the eight carp there are worth $165,000, but others smile. In Japan a champion carp may bring $40,000. It is exactly like America where a nice basic dog can be got free, whereas a basset to end all bassets rightly costs thousands.

When a press person examined the Commerce carp on May 1, May 10 and May 20, there was no orgy going on.

It turns out there has to be a 35-degree increase over minimum winter water temperatures if the carp are to breed, and this is not provided in the heated aquarium.

The ordinary brown carp of Washington waters (all descended from the carp of the Danube, though fate has treated different descendants differently) observed the traditional carp festival.

A fellow who lives in a boat on Swan Creek said "they are bashing around my boat so I can't sleep" and once, when he ventured out in a canoe," they damn near swamped it." Lots of love there in Swan Creek.

The gorgeous beauties of the Commerce basement rejoice every visitor's eye. Such colors, Blue, coral, lemon. But now the great carp season is over. And beautiful though they may be they missed it. CAPTION: Picture 1, The owner of the carp at left reportedly turned down an offer of $20,000 for it.; Picture 2, "Koi in Niskiki-e by Kitagawa" Utamaro.