Fireworm or a beneficial bristleworm?

TweakyReef · May 24, 2019

Hey ladies and gets! So I know my tank has a healthy amount of beneficial bristleworm worms (grey and pinkish, not that large). Though I recently saw one that was questionable... My BTA has recently declined in health, so I've been trying to top him up with food (small bits of prawn) a bit more regularly. The other week I placed a bit in the BTAs mouth and watched to make sure no fish would peck it out, however to my surprise I saw a larger than most bristleworm come out of hiding and snatch the prawn from its mouth! Unfortunately I don't have any photos but will try to get one by baiting it soon. Though are the beneficial types of bristleworms known to present this type of behavior? The chuck of prawn was a bit smaller than an Australian 5cent coin. I know fireworms are know to devour dead fish, but cannot find a source stating beneficial bristleworms eat more than just plankton, algae and dead organisms... Leading me to believe they probably wouldn't eat a chuck of prawn almost the size of a 5 cent piece! I could definitely be wrong, hence seeking some assistance from more experienced hobbyists.

Might be hard to give advice without a picture, but hoping the behavior explained is enough to tell if its a fireworm :)

Thanks peeps!

TweakyReef · May 24, 2019

Just got some pictures! Got lucky and he came right out. It seems that its bristles are quite prominent and white. Sorry for the crappy quality pictures, it was taken from my phone.

TweakyReef · May 24, 2019

I'm about 70% sure it's a smallish fireworm. As soon as I get a majority rules thing going here, I'll remove the poor critter.

Hemmdog · May 24, 2019

I’m with ya, fireworm.

Lasse · May 24, 2019

There is around 10 000 species of bristleworms (or polychaetes) Fireworms is normally those that can sting you. Most of them we see in aquaria can sting. And yes they can be rather huge and eat what they can get.

Sincerely Lasse

reef lover · May 24, 2019

This is the one you want to watch out for...predatory.

DeLegge90 · May 24, 2019

Just got rid of one that looked similar to this from my tank. I set a bottle trap out with some food, turned off the lights, and waited with my tweezers for him to come out from the rock and expose himself, which he did, and then I was able to take him out.

OrionN · May 24, 2019

DeLegge90 said:
...... I set a bottle trap out with some food, turned off the lights, and waited .....

These are scavenger or else they would not go for your food. The specific coral eater and fish eater would go for the fish or the coral, not the bit of food laying around.