When you say “fish fry” to an aquarist, it generally doesn’t have anything to do with lunchtime.
“Baby fish are called fry,” Charley Pratt says. “This is a fry-raising setup over here.” Pratt indicates a row of small, square tanks with partitions in them. “So you’ll see lots of baby fish here. Fry.”
The fry are almost incomprehensibly small. Each one is about as long as the word long in this typed sentence. Hundreds of little fry as long as the word long.
“And then, of course, the mothers, you’ll see one fish to a cell,” Pratt says. “And there’s places in here for the babies to hide when they’re born. Interestingly enough, she gave birth to four young yesterday and they’re not there today, so she obviously ate them. That does happen frequently.”
“I think one of the big draws for keeping tropical fish is breeding them,” says Charley Pratt, who happens to be one of the foremost fish breeders on the West Coast. “For instance, with guppies, manipulating them genetically, coming up with ways of making them look different: more colorful, or different color, or a bigger tail. I showed you that big-tailed guppy back there in the corner. Guppies originated with practically no tail. A little bit of a clear tail, with maybe a spot of color in it. But guppy breeders have created a beautiful thing to watch in the aquarium.”
Pratt used to teach computer information systems at Southwestern College in Chula Vista. His gray hair has disappeared from the top of his head though it still clusters around the sides. His accent is from North Carolina.
Kirk Bean, listening to Pratt talk about breeding, picks up where Pratt left off.
“It’s fun learning about the biology of the animals, the ecology of the systems that they live in, and trying to keep things alive,” says Bean. “The other part of it is trying to breed things that aren’t easy to breed in captivity. A lot of fish have environmental triggers that cause them to think that it’s time to breed.”
Bean has an earnest face and always seems to be thinking deeply about something. He looks sort of like Kirk Douglas, with the dimpled chin, clenched teeth, and blue eyes.
“Let me give you an example,” Bean says. “Had a fish that was very difficult to breed. No one had figured out what a trigger for this fish was. And it turns out that in order to induce it to breed, you let the water get bad. You let the water get stagnant a little bit. You let the water feel like life is bad. And that, in its natural habitat, is what happens during the dry season, when the water flow stops, and the ponds that it gets stuck in start to get low in oxygen, high in temperature, and full of pollutants. So, you let the tank do something that you normally wouldn’t do, which is, become close to dead. And then, all of a sudden, you simulate a rainstorm. And if you can do it when an actual rainstorm is about to happen — when the barometric pressure drops — you then go in and say, ‘All right, let’s just psych out this fish.’ You drop the temperature, as though rainwater has now hit at a lower temperature, you increase oxygen, you increase food supply, and you let these fish go crazy, and, poof! You’ve got fish eggs all over the place.”
These were Bean’s zebra plecos. But he’s also used this technique with a species of wild angelfish that he couldn’t get to breed for three years.
“It’s like playing ten-dimensional checkers,” adds Craig Fries. Bean laughs and Fries says, “Or something along that line. Each dimension you add just gives you a huge number of other variables that you have to consider.”
Breeding Fish, Part Two: And Here’s Where It Starts to Get Weird
“A lot of fish will keep live sperm in their bodies for months,” Charley Pratt says. “The females have what’s known as nurse cells. When a male fertilizes her, the sperm is kept alive on the nurse cells until the female needs it. She could have more eggs come down a month later and just use sperm from that one male.”
Pratt chats as the tanks of his hatchery bubble and glisten all around him. There is motion everywhere. Something in this room is always, always moving.
“Here’s a male and a female guppy,” says Pratt, bending toward a small tank with two little fish in it. “If you can see underneath that male guppy there, the guy with the big red tail, there’s a little straight fin. That’s called a gonopodium, and if you look at the female, she has a big floppy fin there, called an anal fin. So the male’s anal fin is modified into a gonopodium. And he uses that, in combination with his two pelvic fins, to form a little tube, and he goes up, side to side, and he brings it forward, and he just barely touches the female to insert the sperm. He doesn’t really go inside her.”
Bill Cline, who’s been lingering nearby as Pratt talks, chimes in with a quirky breeding story of his own.
“There’s an amusing little fish down in Mexico called a four-eyed fish,” says Cline. Apparently, four-eyed fish have nature’s version of built-in bifocals, and as a result, they can see equally well above and below the water. “They’re also live-bearers, like the guppy. And the male four-eyed fish either develops right-handed gonopodiums or left-handed gonopodiums. And they have to breed with either a left-handed female or a right-handed female. A right-handed male can’t breed with a left-handed female. A very interesting adaptation.”
So it isn’t only mammals that breed live young?
“Guppies, platys, swordtails, and mollies are four of the more common tropical fish that bear live young,” says Pratt. “And there are others. But even more interesting, perhaps, are the mouth breeders. Take these Corydoras aeneus catfish, for instance. If you look down here in the corner, you’ll see some eggs scattered all around.” The eggs look like a teaspoon of tapioca without the pudding. “They have just been spawning. And what happens there is, the female takes sperm from the male into her mouth, and she already has the eggs at that point caught in between her anal fin. She’s expelled them already. And she goes up and presses the eggs to the glass and then puts the sperm from the male right onto the eggs. And generally there are groups of spawners all doing that at one time. Up to seven, eight, or nine of them.”