Watch the females carefully. One will suddenly slim down. They shouldn't be really skinny. Emaciation is a sign of trouble and I'm glad that isn't something you have encountered.

28-30 days is usually the gestation period. Warmer temperatures can speed it up by a day. Crowding, stress, cooler temperatures (and who knows? sun spots, crop circles, the Cubs winning a world series...) can delay the dropping. A Guppylog correspondent even mentioned that an isolated female guppy had slimmed out when there was little evidence of cannibalism. That does seem to happen to guppies and a lot of other creatures. A recently read book on North American habitats noted a number of cases and species (mostly mammalian) where if food (vegetable forage or prey) was not plentiful, then fetuses were reabsorbed. That has been known to happen with humans even.

I don't think that is the case with all of your female guppies. But the more I learn about fish, more more I realize that there is still a lot not known. Sometimes we don't even know the questions yet. :)

Though a female guppy can be trained to cannibalism (often before we even get them) by insufficient feeding, there are other species that will even more enthusiastically eat guppy fry. The first consideration is that "'if a fish can fit into the mouth of another, it will.

You may have seen New Guppy Momma pondering how many dwarf gouramis (and maybe small angelfish) she could stuff in her "Beast" (of 75-gallons). That is a pretty sophisticated balancing act. But it is not too long after we celebrate the effective saving of fry that we worry about too many.

Thank you for plowing through Immediate Help or at least a lot of it. Maybe you saw that little thing on the Better Guppy Trap. The idea is to meet each fish's needs without intruding upon those of another. So we leave very desirable food for the momma and she leaves the fry alone.

With guppy and other livebearer aquaria and even many many killifish tanks, there are several variables, which will yield more youngsters. I'm sure that the list is not complete. Anyone else is more than welcome to add more helpful factors or elaborate upon a point.

more shelter, especially plants
more frequent water changes or an increased % in each change
better seasoned and treated changing water
(sometimes) a lower mineral level in the water
(less often) a greater mineral content for desert, brackish, marine and inland fishes
more frequent feedings, maybe of less food per feeding
more variety in diet (even if just flakes)
more meaty content to feeding
live food (like Daphnia) swimming around the tank
a very modest adult population of killies in the aquarium
larger aquariums - more space per adult and fry
temperatures in the lower part of their comfortable range
only one species in there
no charming but egg-eating catfish - especially look at the size of the mouth (What a big mouth you have Grandma!") and the eyes. Large eyes = a night feeder.

I am really pleased that your nine guppies have seemingly thrived in your new 10-gallon. I wonder if that is about 6 or 7 too many though. I would guess that you have been careful and have conservatively not fed a whole lot. That makes great sense from the standpoint of allowing the nitrogen cycle to develop. But it is at cross purposes with feeding the females until they can eat no more and will leave the fry alone. If your aquarium has been set up for a short period of time, say under a month and a half, that cycle needs to finish.

And - sigh - the fry get eaten. :(

There will be a time when you will be, ahem, swimming in fry.