Can i release my guppy fry with the rainbow shark?

Guppy fry have been raised in a seprate netted grow out box. They are now .75 of an inch. Can i release them into the tank? Its 30 gallon. Live plants (1 crpyts, vallisneria, guppy grass). The only issue is that the last batch didnt survive. Maybe due to the rainbow shark. Can i release them now into the tank? Dont like the look of the netting box in the tank. Also lots of hiding space in between the lava rock.

 

What size were the last ones? I wouldn't if you know the last batch didn't make it!

 

No,you cannot.
Even if it's a juvenile rainbow your fry will be a snack

 

So my only choice is to release the rainbow shark into the other 180 long. But theres another rainbow shark there :/ what do i do? Cant really rehome or do much else because of the pandemic lockdown.

 

So my only choice is to release the rainbow shark into the other 180 long. But theres another rainbow shark there :/ what do i do? Cant really rehome or do much else because of the pandemic lockdown.

I have multiple rainbows together.
Make a few new hiding spots and put him in there.
Who's bigger? The one in the tank or the one going in the tank?

 

Theyre both the same size and age. Ones white (albino?) and ones black.