Growth On Baby Guppy?

So I've been breeding guppies for about a year but have never encountered this. This batch was born about 2 weeks ago. I thought maybe it was part of its egg sack and it would eventually fall off but it's still there. It's pretty thin but it's not a fin. He's acting normally. Eats good. Swims fine. Very active. But I can't figure out what that is. Should I be worried? Sorry if pictures are bad, my phone doesn't focus very well.

 

Could it be poop?

 

Could it be poop?

No cuz it never comes off and it's more on his stomach than near the tail. It's kinda in the shape of a trapezoid

 

Hi! I've posted this before but haven't really received any answers. My guppy has given birth to fry and one of them has this growth type thing on him. He's had since he was barn and he's almost 4 months now. I thought maybe it was part of his eggsack and that it would eventually fall off. It's kind of trapezoid shaped. It a little thick at the beginning but gets thinner as it ends. It doesn't effect his swimming. He eats normally. Does anyone know what it could be? (Sorry I could only get this picture, he's a pretty active swimmer) (also they are in a breeding container until their new tanks cycles for a few more days)

 

It's most likely a siamese twin. It happens and one will develop in a normal way and the other remains undeveloped.

 

It's most likely a siamese twin. It happens and one will develop in a normal way and the other remains undeveloped.

That's interesting. I've never heard of that. He should be fine though right?

 

That's interesting. I've never heard of that. He should be fine though right?

This happens more often than you think. And like I've already mentioned, one will develop normal and one won't.
It won't hurt or bother him at all. So, he will be just fine.