But you got me re-reading aurora's log a couple of times. Got a second cupa coffee and looked again. Still nothing on breeding traps. ;)

If you have browsed my A Better Guppy Trap in the Immediate Help section on breeding, you get a felling for my preferences for pregnant livebearer females - evacuate everyone else, feed her well (if she isn't bloated) so her hunger will not lead her to dine on fry. Lots of plants offer hiding places. (Actually lots of floating plants like water sprite and bottom thickets of Najas and/or Java moss are an almost unbeatable combination. I was naturally really pleased to see what aurorahorse was doing with planted 55-gallon tanks.

And there are different schools of though here too. On the old livebearer's mailing list, I provoked an, ahem, spirited response from Detroit area livebearer guru, James Langhammer. The discussion wasn't on guppies but wild-type livebearers. I was recommending removing females (of a species famous for their cannibalism) after dropping fry. Jim felt very strongly, using 20-gallon to very big tanks, that wild type livebearers were best served by being bred in colonies, with lots of shelter, hiding places and food.

Mine at the time was a very busy work schedule, which meant that feeding was by fits and starts and the said aquarium was only a well planted 15-gallon. Neither of us are right or wrong. Both systems have to do with the time, space and energy (both mechanical and personal) available to the aquarist.

The plastic "box o' death" which we take turns beating up on in the IH log of the same name, is a 3" x 3" x 6" (7.6cm x 7.6cm x 15.24 cm) completely enclosed floating plastic box with no flow in or out of the main tank. A result of this is that the female may panic and suffocate as the material she regurgitates or passes, fouls the water. Another draw back is that she may go into shock when closely confined. Lastly guppy fry statistically go up more often than down through that little v in the bottom of some of those traps - leaving them right in front of mama.

If there is a top light, guppy fry may be especially inclined to go to the surface. That can work against us and the fry or for us. For instance newly hatched baby brine shrimp are also phototropic and so they and the hungry fry meet at the surface area of the aquarium, under the light.

About a year ago, TFH published an article by a young man (that is not a criticism, I think research from a person, who at the time was probably an eighth grader or high school freshman is terrific) which observed where newborn fry went. Using drum bowls, he noticed that fry immediately moved to a different level of the bowl than the level the adult(s) was/were at. Scott Lockwood's theorem of fry avoidance is that the adults eat the malformed and stupid ones who stay around and make themselves vulnerable to predation. :0

Breeding nets still have their limitations, but allow females, fry or wounded fish the beneficial water flow and other benefits of a larger aquarium. There are evidentially plastic gismos now-a-days which also allow flow through currents. I would still avoid those plastic gizmos, but if we have limited space, they might be useful. A person may feel, "Better five fry than none."

The thing to remember about containers hanging on the tank side is that guppies - and especially very pregnant guppies - are not single Bettas. And for the record, almost no one would try to breed Bettas in a tank smaller than 10-gallons/ 39 L, even though, with lots of shelter for the female, it can be done in a five. (But it is a dickens getting the female out without messing up the nest.)

Behaviorally, virtually all fish have (obviously) evolved to need more space than we provide them in aquariums.  During stressful times of pregnancy, quarantine or illness, in an effort to give them a place of their own, we usually put them in less space. In a more perfect (and more affluent) world, we would give them MORE space in those circumstances. :)