danio lump on chin

[Harriet]

one of my zebra danios has a lump on his chin and has had it for a while he might’ve even had when i got him and i just never noticed it it’s like the tiniest little growth on his lower jaw and it’s the same colour as his body you can’t see it from the front could this be anything dangerous, or is it just a weird deformity?? he’s eating and swimming fine i first noticed it about a week ago but couldn’t get sight of it again so i though i was just seeing things but no it’s definitely there