Clownfish fry hatching at different times

[swill]

Is it normal for a few clown fish fry to hatch one night as the rest remain eggs on the rock they are attached to?

This happened last night. Its day 9 of the cycle and last night I waited about half an hour to an hour after the lights went out to shine the light in on the tank. I saw one little fry so we siphoned it out into a clean bucket. About 10 minutes later there was another and then another. I had 3 clown fish fry in my bucket which was half full of the same aquarium water and waited about another hour but no other egg hatched. I took the bucket and gently poured it into a clean dry 10 gallon with an air stone and small heater and turned on the light to see 2 of the 3 already dead. The third was still alive when I went to bed but it was already nose diving so I knew he wouldn't last long. I can't find the third one this morning but I assume he also didn't make it.

Do you think maybe these 3 were born premature and died because of that or do you think I did something wrong? Is siphoning fry too much for them? Has this ever happened to anyone else?

I assume the rest will hatch tonight but I obviously don't want to make the same mistake, if I even made one.

Thanks for the help.