He looks an OK size - I mean I don't think the adults will think him food, will they?
He has been among them before with no problem.
Thing is that every time I saw a fry acting strangely, they would shortly become food that very day. Which is why I put my remaining 2 big fry in a fry net again.
Pinky, Hoppy and Chrome stand as examples.
Pinky was pretty near the 3cm / 1.2 inches. She ate 3 bloodworms, looked exactly like Ninja a day before, and then the next day, she was gone. None of the adult fish, not even the hoplo, had a mouth THAT big. Yet, she was gone.
Hoppy was near Pinky's size. Last time I saw him, he refused to eat with his siblings. Gone 4 hours later.
Chrome - the same day Hoppy disappeared, Chrome was acting weird (fast breathing, sitting on the sand), but no fish was attacking him, all of them just avoided him and left him to rest on the sand. At night, Chrome went to the surface and his tail was hanging. I only took my eyes off the tank for 30 minutes, when I looked back, Chrome was nowhere to be found. I looked everywhere except under the Java Fern (and doubt any fry would hide there).
Ninja and Sushi were the only fry to survive the big tank, as my newest addition, Arrie the lyretail, ate all the tiny fry that the other adult fish would not mind having around. Those were 1 cm fry that I haven't even named.