Spider looking critter id please

[goody]

I put some of my euphyllia and goniopora in a holding tank before moving to my new build. I knew I had red planaria, so I was using FWE. Bought a couple euphyllia and put in the tank also because there were flatworms in the bag. Decided to do a hydrogen peroxide dip on my gonis which have encrusted on an egg crate. 2 of the spider looking critters came off the egg crate. Any ideas what they are?

 

[DaJMasta]

Those are sea spiders. If they're on corals, they're likely coral predators, but in my experience, coral dips are very effective against them.

Creepy looking things, only seen once on a frag of zoas in person before.

 

[goody]

What coral dip do you recommend? Or is there an intank treatment I can use? Other than a few gonis, it's all euphyllia in this holding tank. I only noticed them as they became actively moving around with the hydrogen peroxide dip. Do I have to worry about eggs?

 

[DaJMasta]

I don't know about a whole tank treatment, but Coral Rx Pro (and probably any similar tea tree oil based dip and likely others) should kill them pretty quickly (jump off and scrunch up.) And at least in my case, whatever eggs they may have or carry seemed to go away with the treatment - maybe they carry their young and they die if the parent does, maybe their eggs are susceptible to the same sort of dips.

If you're not sure where they are, you could try pulling some frags of different species and just seeing if they come off in a dip. If you find one with them, you know their food source, but in my case it was on a zoa frag which didn't look particularly damaged.

There's some chance they're detritivores or something relatively harmless, but I don't know of great resources to ID them to know for sure. Spiders tend to be rarer in the hobby, I think maybe a combination of them not being particularly durable and probably that a bunch of treatments kill them effectively.

 

[fishguy242]

they carry their eggs on them

 

[UMALUM]

I put some of my euphyllia and goniopora in a holding tank before moving to my new build. I knew I had red planaria, so I was using FWE. Bought a couple euphyllia and put in the tank also because there were flatworms in the bag. Decided to do a hydrogen peroxide dip on my gonis which have encrusted on an egg crate. 2 of the spider looking critters came off the egg crate. Any ideas what they are?

A simple 2 or 3 second swish in fresh ro will get rid of them as well as any flatworms without the cost and stress of any dip.

 

[goody]

Since I had them in a separate container, I put some Bayer in and it killed them.
May try this or some fresh RO on the frags.