My husband and I kept the first Betta fish (red, quick) in a bowl—itself like a fist-sized drop, a temporary planet. We hoped the fish would do something for us. The summer had been one long heat-wave, and the failure of our marriage bore down. We could have split up. If we had, there wouldn't have been any tangible losses or gains. We were young; we didn't yet have children, or any money. But we were desperate to stay together—to remain in that snoozy town, in a brown-brick housing complex inhabited mostly by elderly widows and widowers, in our tiny, low-ceilinged studio apartment. Inside it, the air shimmered and rippled with hostility—but we couldn't leave. Neither of us had anywhere else to go. We had no one else to be.

At first, the Betta fish provided some relief. "Fighting fish"—this alternate name for its genus made us laugh together for the first time in months. "Fighting fish," we'd say, each f launching flecks of saliva from our mouths, his aimed toward me, mine at him. It was joke, a parody of the anger that, before we got the fish, had not been funny at all. A strange vibrancy came upon us—the Betta a ruby glint in the corners of our eyes.

We named it Benny, another joke because that was his name—my husband's. I'd come home from work and say, "Hey Bennys, how were your days?" Now, instead of two, we were three. By the second week of August our laughter dwindled, but the silence that replaced it wasn't as awful as it used to be. When my husband and I spent whole evenings not speaking to each other, it seemed possible that we were doing so not out of rancor, but out of respect for the creature among us who had no vocal chords. When we quarreled the fish kept swimming, ignoring our outbursts—complicit. "You're the love of my life, Benny," I once said, and my husband and I cracked up. The punch-line was that neither of us knew which Benny I meant, and either way my declaration was preposterous. By mid-August, the laughter stopped altogether.

Betta fish will gnaw each other to death. So when we got a second one, this time blue, we gave it a bowl all its own. Watching the two of them swimming—flying—it seemed like destiny: this side-by-side configuration had been the plan all along. We called the new fish Sapphire. Every day or so, either my husband or I moved the bowls a tiny bit closer together. Neither of us ever saw the other do it, but it kept happening until the bowls touched. We said terrible things, speculations that seemed to border on hopes: "What if one fish leaps out of its bowl into the other?" "What if the fishes' inability to kill each other drives them insane?" By the third week in August we had stopped speaking to each other completely, unless it was about the fish. My husband said: "What if they both ram the bowls with their heads, trying to get at each other, until they shatter the glass?" I said: "What if they really do go crazy, and each fish fights itself to the death?"

But the fish didn't do what we expected. No, they didn't charge the glass in-between, not even one stiff glance. Their circles were private, neat, clean. Together my husband and I waited, our teeth set hard, top pressed down to bottom—the air between us snapped tight, while the Bettas swam their tranquil circles. We watched them die from a mysterious algae; somehow despite their separate habitats it infested them both. Scales shook off them like spices, or flakes from a croissant—the color of them, one blue and one red, in crumbs on the surface. Finally we witnessed them float up like balloons. We tossed them out the door, into a bush. Other animals could fight over their bodies. It was OK. They had failed to rid us of our resentments, the ones that spiked from our backs like wings—the ones that kept us quiet that August, that whole hot month like a welt.