I hear people say, "I wish I lived back in (name you famous time period)". I don't think they realize how hard and manual life was then (or as Thomas Hobbs said, short, hard and brutish (or something like that).

Having said that, I'm pleased to be corrected by Nancy, who has suggested that feeding egg yoke in a limited space would work. She is careful enough to watch that floating box carefully. For all we know, she is changing out the water a little while after feeding the fry the egg yoke and refilling it with water from the larger aquarium it is floating in.

I'm still leary of keeping fish in small containers. In our last two frantic weeks of tearing down and moving aquariums, I'm found a lot of fry and have pressed a number of bowls, small aquariums and jars into service. Some things are being used for fry who should have had larger quarters. In most cases they have worked as temporary quarters. However I did lose a batch of tiny, tiny dwarf rainbow fry (M. praecox), though not before taking photos. (You think guppy fry are tiny!) There was also the ugly case of a Rivulus fry eating his same sized partner in too small a bowl. (Yeactch.)

So, try the egg yoke in a small container, then drain off much of the water from the small container and replace it with water from the active aquarium the fry came from. Leaving a small snail or two (you know what that will do if there is lots of food) to clean up in that container is probably worth whatever demand upon oxygen they make.

Nancy and fishfishla, you've got me thinking about what can be used in feeding a redworm culture I would like to establish in a 40 gallon plastic household storage container and whether powdered agg yoke could be feed lightly to 40-gallon daphnia cultures out side (where the wind does greatproviding O2). In the course of cleaning out all manner of shelving and storage containers accumulated over the past 25 years (and I'm still only 23), a number of old fish food containers turned up. Soaking the old fish food with liquid vitamines and feeding them to the worms or feeding old microfoods to the Daphnia seem like thrifty ways of using those items and cleaning up the house at the same time.

That is in fishfishla's tradition of thrifty fishkeeping. And why don't we declare fishfishla our Frugal Aquarist of the Day! :)

And Nancy gets to be my conscience, especially with Miskairal island hopping. ;)

Aquarists (1900-1955) would feed a little of the powdered egg yoke when they couldn't get "pond water." (You eat the egg white, unless you have a dog which envies you for everything you eat.) They didn't have brine shrimp eggs to hatch and feed. They didn't have any of the zillion commercially produced fry foods we have.

I don't know if they had microworms or vinegar eels. Probably did have some live foods, in season, which we don't use much (seived Daphnia, mosquito larvae).

You run the risk of fouling the water if you over feed and a sizable snail team doesn't clean it all up. You'd probably catch the mess and change the water before a bacteria outbreak or suffocation set in, but why go through all the hassle. :)

The most convenient source of fry food, as lomelindi noted, if there is enough, is to scrape the powder off of the parent's food cannister. One can hatch small quantities of baby brine shrimp daily, but it should be fed within a few hours of hatching for best effect. (See the Immediate Help section for more.) There have also been a lot of fry food suggestions, made by Guppylog people in the Immediate Help section and elsewhere. If you really want to get crazy, Google [Guppylog fry food]. After 7 pages of references click on "repeat the search with the omitted results included." If you Google [Guppy fry food] it really gets out of hand - but will you be an authority! ;)

Also, stop by your LFS and ask them what they have available. I can appreciate you wanting to try gently scraping hard egg yoke and watching to see how the fry fair. And maybe someday I'll try that. But results are likely to be better with the prepared stuff. And that may justify spending more on the prepared foods than on an egg every now and then.

I know that sounds terribly unadventurous, suggesting not using powdered egg yoke. (Heck there is probably a commercial source for that too. Sure enought, half a pound for $4.50 plus shipping.) If you want to try, the worst that could happen is that you would lose the fry in the fry tank. Don't risk the adults by feeding the egg yoke in their tank. In another tank, your adults will produce more fry anyway.