How Can I Lose All My Fry?

[Ny82]

Hi I am having a frantic panic moment. I have a 64L fry tank, temp about 28/29, 1 endler cross, 3 newborn guppy fry. 1 platy and her 2 fry. 
In the trap I have cory fry. I have about 30 fry who hatched on friday and 5 who are about 3 weeks old. The trap has tights round it to stop them escaping out the trap. Today the 5 bigger ones are there, the rest are missing. 
 
yesterday

 
today
 

 
I took the tights off it in case they slipped out the vents and got trapped in between the trap and the tights. 
 
It usually has the airstone in it, I took it out to take the pic

 
1 left

 
fry tank

 
How can I lose all the fry? Could the trap have tipped and they swam out? Could there have been a gap and they swam through the vents into the tank? I just don't get it.
 
Tank stats this morning
ammonia - 0
nitrites - 0
nitrate - 20-30
PH 6.4
 
What's going on? Surely the bigger fry haven't ate the smaller fry. I had so many. I'm so frustrated and angry. How can they all have disappeared?

 

[Tim_UK]

I would think the bigger cory fry ate their little brothers and sisters.

 

[Ny82]

Really? I read somewhere that cory do not eat their own fry. I have bred guppies for the last 2 1/2 years, they are bad for eating smaller fry but I really didn't think cories would do it. The guppy fry used to hide out in the caves with the cories-they weren't a threat. Gutted

 

[Chad]

My first thought is escape. Is there any way they could have jumped our wiggled out?

 

[Ny82]

That's what I was thinking too. The trap itself was hooked onto the top of the filter and the other end hooked onto the thermometer. I looked this morning and thought it was tilting, the filters low so the water level could have been the same as the trap. I don't know but all of them?

 

[Chad]

It's possible they found a clear way out. Fish near the surface office feel vulnerable and want to head down to deeper water. I float some frog bit over my nursery net for that reason. Certainly being eaten is a possibility, as has been pointed out that does happen.

 

[Ny82]

I got the fright of my life when I moved a rock in the main tank-about 3 or 4 little fry darted out! That will have been the eggs I dropped whilst removing them.
They could be hiding if any got away, I wish at times like these I had white substrate not black in my fry tank so I could spot them! No doubt the parents will spawn again but that's not the point. I am very sad about this.

 

[Chad]

Sorry it happened.

 

[Ny82]

It's ok, always me. The 5 I have who are 3 weeks old, had a similar disaster. The fry trap tipped and I didn't notice. 5 left out of about 40 - keeps it manageable I suppose

 

[Chad]

It does. After a while the tank simply can't keep up. That's why I generally don't net them unless I have a buyer.

 

[Ny82]

It does. After a while the tank simply can't keep up. That's why I generally don't net them unless I have a buyer.

 
I had 4 people wanting groups of 6 each. Nevermind. 

 

[Chad]

Yikes.

 

[Ny82]

I didn't promise them anything, it's like with any fry, you don't know how many will survive until adulthood. They were just friends who said oh I will take some then they tell someone else then they want some then word spreads lol. 

 

[Chad]

Clearly you have conditions right for breeding so there will be more! Feel sad for a while then forge ahead.

 

[Ny82]

I didn't even think about breeding, first spawn was when I lowered my temp for my platies. 2nd spawn I had been away to my parents for the week and came back on friday to eggs everywhere. The tank lights had been left off because of the heatwave the temp managed to stay at 24.
Now that I want them to spawn they wont! I wont do anything different, just leave them to it, that's the best way. Trying to interfere usually causes problems!