Fry of what fish?

And seriously, I can't think of a reason to have the lights switched on 24/7 - even fry need to sleep, and even plants need to "rest & breathe".

If it is fish fry - keep them in a LARGE tank, with good water parameters & proper feeding, and they'll grow large very quickly (though not necessarily maturing faster).

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~ John ~
I am a Malawi Fan!