What kind of a worm is this?

[MarinaClown]

Just saw this in my tank right by where one of the hermit crabs was messing around a snail shell. Or is that a snail that ran away from attack?

 

[Lucasb625]

Bristle worm

 

[MacDracor]

Lucas is correct. That is a very common species of bristleworm. Extremely beneficial scavenger. Won't hurt anything and keeps the tank cleaner. Good guys to have!

 

[MarinaClown]

Thanks. I feel relieved. It was eating the dead snail.

 

[MacDracor]

That's what they do best; eat dead things before they rot and kill other things. In the past, they've been accused of killing then eating but we now know that they will not attack healthy animals, even slow moving or sessile ones. If they're munching, it's already dead or dying.
There are a couple predatory species, but they either have very specialized diets (gorgonians for the Caribbean bearded worm) or are VERY recognizable (bobbit worm). Rule of thumb, 99 times out of 100, and unidentified bristleworm is still a good one!

 

[MarinaClown]

That's what they do best; eat dead things before they rot and kill other things. In the past, they've been accused of killing then eating but we now know that they will not attack healthy animals, even slow moving or sessile ones. If they're munching, it's already dead or dying.
There are a couple predatory species, but they either have very specialized diets (gorgonians for the Caribbean bearded worm) or are VERY recognizable (bobbit worm). Rule of thumb, 99 times out of 100, and unidentified bristleworm is still a good one!

Thank you. Very informative.

 

[MarinaClown]

Incidentally Orchid Dottyback is the next (last) fish on my list to add and supposedly it can eat the bristle worm...oh well.

 

[MacDracor]

Quite a few marine animals can and will eat them. Luckily, they are good at hiding!