Huge Bump Near My Guppy's Tail! Help Please

[Jennm62]

I just recently saw that my male yellow tailed guppy has a huge bump right before his body connects to his tail. One side, it has 1 bump and the other side of the fish it has two..

Here is the best picture I could get of it.

does anyone know what it is/what it could be/is it deadly?

I've had him for about 5 months. It also appears a small bump is growing on his actual tailfin

i'll attach another picture with a reply.

here is the 2nd pic

 

[WILDER]

Size of tank in gallons or litres.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.

The pic is to small i'm afraid to make much out.

Is the bump beneath the skin or on top of the skin.
What colour are the bumps.
Does the bump look hard or soft like filled with fluid.
Does the bump look smooth or resemble a cauliflower.

 

[Jennm62]

5 gallon
6 guppies, 1 cat fish

do not have the stats,
and I'll repost a picture, it looks like a cauliflower type bump where his scales kinda stick out. Bump is inside his skin (it appears) and it's the color of his body