I'm trying to remember the title and author of a short story I read years ago.
"The Ethical Equations" by Murray Leinster (pseudonym of William Fitzgerald Jenkins), originally published in Astounding Science-Fiction, June 1945, available at the Internet Archive.
It concerned a deep space exploration ship that comes upon an alien ship.
Deep space in this case is the outer solar system, beyond the orbit of Jupiter. The alien ship is from a distant star.
The alien crew is in hibernation.
"It presents several problems, sir," said Freddy evenly, "and that's one of them." He was rather pale. "The ship is empty of air, but her tanks are full. Storage spaces containing what looks like supplies are only partly emptied. The crew did not starve or suffocate. The ship simply lost most of her fuel. So it looks like they prepared the ship to endure an indefinite amount of floating about in free space and"—he hesitated—"then it looks like they went into suspended animation. They're all on board, in transparent cases that have—machinery attached. Maybe they thought they'd be picked up by sister ships sooner or later."
The investigating crew wants to salvage the ship because it is made up of all sorts of exotic materials never seen before.
"Try to figure out what that ship's worth!" he said happily. "It's all over the Arnina. Prize money isn't allowed in the Patrol, but five percent of salvage is. Hydrogen three has been detected on Earth, but never isolated. Lithium five doesn't exist on Earth, or glucinium eight, or nitrogen fifteen or oxygen seventeen or fluorine eighteen or sulfur thirty-four or thirty-five! The whole ship is made up of isotopes that simply don't exist in the solar system! And you know what pure isotopes sell for! The hull's practically pure iron fifty-five! Pure iron fifty-four sells for thirty-five credits a gram! Talk about the lost treasures of Mars! For technical use only, the stripped hull of this stranger is worth ten years' revenue of Earth government! Every man on the Arnina is rich for life! And you're popular!"
A lowly ensign shows that it can't be salvaged because the materials are unstable at warmer temperatures. He took shaving from the ship and put them in a rescue flare and the contents explode when it warms up.
Actually he's a lieutenant junior grade.
His spacegloved hands worked clumsily. From the tiny kit he spilled out a single small object. He plopped it into something from a chest in the spaceboat—a mortar shell, as Bridges saw incredulously. He dropped that into the muzzle of a line-mortar the spaceboat carried as a matter of course. He jerked the lanyard. The mortar flamed. Expanding gases beat at the spacesuits of the men. A tiny, glowing, crimson spark sped toward outer space. Seconds passed. Three. Four. Five—
"Apparently I'm a fool," said Freddy, in the grimmest voice Bridges had ever heard.
But then there was a light. And such light! Where the dwindling red spark of a tracer mortar shell had sped toward infinitely distant stars, there was suddenly an explosion of such incredible violence as even the proving-grounds of the Space Patrol had never known. There was no sound in empty space. There was no substance to be heated to incandescence other than that of a half-pound tracer shell. But there was a flare of blue-white light and a crash of such violent static that Bridges was deafened by it. Even through the glass of his helmet he felt a flash of savage heat. Then there was--nothing.
I think the ship was described as sort of fish shaped
But now the hunk of matter turned out to be a fish-shaped artifact from an alien civilization. It turned out to be important. So the situation was one to make anybody steeped in Patrol tradition grind his teeth.
with the drive engines in the nose.
"We hunt for an entrance port," said Freddy curtly. He added: "Those openings that look like gills are the drive tubes. Their drive's in front instead of the rear. Apparently they don't use gyros for steering."