Its been two weeks now and the fry are proceeding just fine. There are now 50 or so free swimming fry which hang roughly in two groups. The larger and darker colored tend towards the top of the tank and the smaller lighter (presumably younger) spend most of the time at the bottom.
After a short while I began to question the idea of keeping some of the gunk from the large aquarium in the small one. For one it made the water stink in rather short order. About a week ago I set about cleaning as much of it out as I could without totally disrupting the setup. I managed this by sucking the gunk up off the bottom with an old turkey baster and putting it in small increments into a small white saucer. With the help of a magnifying glass I then found the fry and eggs in the dish which I sucked out with an eye-dropper and dropped into a jar. This process, over a few hours, managed to get most of the crap off the bottom.
I have been feeding Wardley liquid fry food since the beginning but at no time did I see the fry engage in what I would call feeding behavior, in fact they tended to run away from the cloud of food rather than towards it. This behavior continued for a while without any indication that the fry had come to consider the liquid as something they should eat. A short while ago when the lights were off I discovered that it was significantly easier to see the fry from the side when the room was dark and they were lit from above with my mini-maglight. At one point when the beam of light struck the side of the aquarium I could see that it was swarming with microorganisms. Suddenly the answer to "what the heck are they eating" is clear. It now occurs to me that the youngest still spend most of their time on the bottom or by the tank side. I can only assume that this bounty of tiny critters it due to the first few days when the water sat on the dregs from the parent tank, fed by the liquid fry food.
The larger fry are now showing some interest in powdered flake food. Though I am not completely certain that they are eating it (its hard to see much at that scale) I intend to continue dropping it in a few times a day. I have gotten into a daily routine of cleaning the larger chunks off the bottom of the fry tank with the turkey baster as detailed above and then drawing the tank town to half capacity. The water is then replaced with water from the parent tank which is brought back up to capacity with fresh water. This keeps the fry tank pretty clean despite the large amount of uneaten food which I believe helps preserve the microorganism culture.
