Help ID these please?

[sravja01]

Hi,
As this is my first post so would like to say Hello to everyone.
I have recently acquired this hobby and everyday learning something new.
Could someone please help me identify what these things are in my tank.
I am very worried that something is horribly gonna go wrong :worried:

With reference to image 1 - these have started to be spotted in abundance quite recently and have witnessed literarily lunged at one of my coral frag and ripped it in bits :furious: They seem to retract quite quickly when approached with tweezers.

With reference to image 2 - they swarm in numbers at night and are all over :eek2:

With reference to image 3 - am pretty sure I have been cursed with Bristleworms. They have started to grow in numbers and in size. I first started to remove them with tweezers but have also started using a trap bought from a local store. On the average I remove 14-15 per night but I am losing to them as they keep on populating :sad1:

Can someone please ID them, comment if they are safe and if not how to remove them.

BTW I have also introduced 3 Hermit Crabs, 3 Snails and 2 very shy Scarlet Shrimps (seem to do nothing but hide behind the rocks).

Many Thanks,

sravja01

 

[LeslieH]

The first image shows the arms of small brittlestars (ophiuroids) living in the rock. These micro-stars are usually quite harmless detritivores & scavengers so it's interesting to read that they tore one of your frags apart. I wonder if your frag was already sick which is why the micro-stars started on it.
The second is an amphipod. As long as it doesn't belong to one of the predatory species -which seem to be fairly rare in the hobby - they're fine detritus eaters & fish food.
You're right. Amphinomid polychaete - for which fireworm is a better name than bristleworm - is the third. This particular type is a detritivore. If you're having a population explosion it's a pretty good bet that you're overfeeding the tank. Cut back on the food as you pick them out & the population will stay down to normal background levels.

 

[sravja01]

Thanks for the reply.
I have cut down feeding my Fire Shrimps. I used to feed half a cube everyday but now do so every other day. Is this too much as well?
Also I feed my corals Gamma NutraPlus Reef Feed 1ml daily. Should that be stopped as well?

I am using a trap for the worms and have caught approx 12-14 daily. I think my efforts are paying off cause the population has dropped (or they have out smarted me).

Any suggestions with Brittlestars? There are plenty growing but there is one which is very huge and ripping my frags apart. How do i keep them at bay? Is 6line or arrow crab a good option? Some say they are reef safe while other believe they are terrorists.

Thanks,
sravja01

 

[Ethan_W]

the brittle stars from image 1 are completely harmless. i have probably a hundred in my tank and none have ever harmed any corals. all they do is scavenge and i like them.

as for the bristleworms they arent really harmful either and they are good scavengers/detritus feeders. i have only 1 in my tank that started at an inch and is now at over 4 inches. fortunately it hasnt multiplied at all (are bristleworms asexual?)