how to clean rearing tank?

[mpg]

i've been trying a lot of different things trying to raise some zebra danio fry.  i thought i had finally figured out a good setup.  but last night i did a minor vacuuming which stirred up some gunk and a majority of the fry died by this morning.  :'( there are only 3 left.

i have a 2 1/2 gallon mini-tank with a corner filter.  i threw a handful of gravel from the main tank to try and keep the biofilter seeded.  the corner filter kept the water cleaner than other methods, but it is always cloudy due to the fry food.

other previous attempts i had tried were:
- a netbreeder.  (the net got gunky and all the fry died one day after 2 weeks)  n2*
- separate container with no filter, but 50% water change daily.  (water changes seemed to shock the fry as half of them died after each change.  n2*
- i put the whisper filter (100gph) from the main tank on the mini tank.  (cleaned the water, but it was like a whirlwind in there with all the fry being swirled around)  n2*

i'd like to hear about some of your successful small rearing tank setups and methods of cleaning the fry tank.  i hope to improve my odds.  i live in a small apartment in NYC, so i can't do anything elaborate.  also i'm just raising the fry for fun (and learnin') not for profit.

[luvfishies]

No gravel would help with the detritus issue.

the sponge filter is probably seeded already if it has been running for a bit. If not, wedge some foam from the established tank on there to keep the biobed viable.

Daily waterchages using airline tubing is a great way to go in a barebottom tank to get excess fry food up with minimum fuss.