Filtration/Water Quality Issues with Fry

[Brandon]

I had several thousand Koi eggs to hatch in a fiberglass container that is about 250 gallons. I have 4 airstones running and some Anacharis, Hyacinth, and water lettuce floating in there. Obviously, I can't run any type motorized filter (these are basicly swimming eyes in there). I do not have a cultured sponge filter. I added some cultured bio balls from a pond bio filter. Water moves in there but not enough to keep bio balls circulating around. They just hang still in different areas. Are these going to be of any benefit this way? Does anyone have ideas on how to siphon some of the water out without sucking up the fry? Keep in mind they are tiny and very thickly populated throughout the container. Ammonia and Nitrite levels are ok now but I worry about them remaining ok over time, especially as the fish grow some and considering I'm feeding them quite a bit. Would Ammo Lok or Cycle be an option to consider? Thanks for any suggestions.

 

[loganj]

Have you got a large sponge? Like the one we used on Pro Eyes tank? I think you could attach a large sponge to a power head and pump some water through a bio barrel without losing any fry. Maybe use one of the MJ 600's. Call me and we'll come up with something.
BTW, where's the pics of the unidentified critter?