yup, thats spawn alright. wait until your whole tank does that. looks like you dumped a gallon of milk in there. i have hade a dozen or so mass bristleworm spawns and i dont worry about it. the corals and the filter and the skimmer clean it up, plus any of your fish that eat little critters will help too. i didnt notice any massive population explosion of bristleworms in my tank. it looked pretty cool the first time. there was 20 or 30 of them spawning at the same time. shooting lines of white everywhere. scared the crap out of me then my husband said he had seen it happen a bunch of times and he thought i knew about it. also if you indeed have a fire worm you want to get him out of there. some of them are predatory, and will kill stuff.
