Do Fish Groom Eachother?

[BelldandyShanny]

Seems like an odd question really, but I've seen a few times my yoyos, sae, and even my guppies look like they are grooming my pearl gourami.  He even looks like he's letting them do it, up to a point.

 

[SouthernCross]

I've seen my clown loaches do it to a Severum. Tr Severums even seemed to lay on his side a little to help them.

 

[BelldandyShanny]

it's so weird, my pearl will either point his nose up, or down and just let them nibble on him.