Help! Tetra fry trapped under UG filter plates!

[fry]

When I set up my 20g community tank I put in underground filter plates before the substrate went down, just in case I needed it "some day", so no power head has been installed on it.  My 10g guppy tank resides just below it, and fortunately I have access to see the bottom of the 20g glass.  

On Saturday past I noticed that in addition to two new emperor tetra fry in the main tank, I also have about a dozen emperor, lemon and cardinal fry living quite happily (for now) underneath the UG plates!  AAARGH!  First thought was:  How the heck do I get 'em out?!   :shock:

So yesterday morning I opened up a little hole in the plates and attached a clear power head tube (the thing that the head sits on) to the hole, and routed the top end of this tube into a breeding net.  Then I sat back and waited for the fishies.  But after 24 hours, no one has ventured to the breeding net.  They're mighty interested in the tube (including one very large lemon baby who is very quickly running out of vertical space to swim in), but they're spooked by the ever-attentive adults outside it waiting for "lunch" and won't venture up to the top.  

I want to save them, but without introducing suction in there, I'm scratching my head over how to accomplish it.  The last time I had emperor tetras breeding in my tank, about 10 years ago, they grew out successfully in a huge clump of java moss, but unfortunately the only place they have to hide in this tank right now is a clump of cabomba and a section of artificial grossostigma spawning mat I put in there.  It's worked so far for the two brave little souls who've been clever enough to avoid the ever vigilant chocolate gouramis who have gotten quite plump on what I suspect are their unluckier/slower brethern.

All three tetra types are constatntly spawning in there, but are obviously eating everything that doesn't ecape through the UG plates.  The tank has been set up three months, and the one big lemon tetra baby must be nearly that old considering the size of him.  I estimate that he's 3/4 the length of the adults.  All the other fry are 1 cm and smaller.

I'd planned to breed these three deliberately when I'm fully set up with proper breeding tanks, but I guess their call of nature couldn't wait till *I* was ready!

Does anyone have any ideas?  I'm at a bit of a loss here.

Many thanks

[pegasus]

Here what I would try...

You should have a hole in your underground filter in one of the corner of the tank, right? I would find or cut a piece of glass or plexi just a bit larger than the depth of the tank. Put the glass on one side of the tank, push the glass past the hole and further, pushing the adult on the other side. Secure the glass and remove the tube. Add some camouflage, hiding space away from the hole, subdue light and food should also get them out of the hole. Then place the tubing back when the last one would be out.
NOTE  An opaque wall so the fry can't see the adults.

Let us know how it went.

Michel

[fry]

Hmm, good idea.  The only problem is that the tank is fairly heavily planted, and I'l prefer not to dig up all the plants and structures if it can be avoided.  

Thanks Michel!

[fry]

Well, it seems like there's finally some success to report.  I replaced the tube and breeding net with just a clump of the fake spawning mat on top of the flange, and banked the substrate around it so the fry can't see the big guys oggling them as they contemplate their escape.  

It seems to be working better, and two brave souls have joined the main tank.  The one I was most worried about, the big baby lemon tetra, is one of the escapees, so my main worry is abated now.   I've plugged the hole in the flange with some balled-up fishing line, to keep the otos out while still allowing the little guys to escape if they want to.  

As odd a setup as it appears to be, I accidentally ended up with an effective under-gravel egg hatchery!  Which is probably just as well considering I'm looking at the tank now, and the emperors are at it again...