Isopod ID - Sphaeromatidae?

[YoungReefer00]

Hi everyone, I was just looking in my tank with a flashlight when I saw a couple of unknown isopods crawling around my Zoanthid coral, these isopods seemed to be eating away at the fragplug. I went to google to see if they were harmful since i’ve never seen them before and I only came across some very limited information. As far as I can tell now these isopods are either harmful Cirolanid’s or harmless Sphaeromatid’s. The isopods that I have in my tank have 3 “tails” instead of 2 that I see in pictures of Sphaeromatid’s, also they dont curl up into a ball as far as I can tell. Cirolanid’s are supposed to have big black eyes but these dont seem to have any.. does anybody know what I am dealing with here and if they are harmful?

 

[Reefkeepers Archive]

@ISpeakForTheSeas? At least they're not zoa spiders

 

[YoungReefer00]

@ISpeakForTheSeas? At least they're not zoa spiders

I don't know what is worse.. zoa spiders or blood sucking fish killers

 

[Reefkeepers Archive]

I don't know what is worse.. zoa spiders or blood sucking fish killers

Should rephrase that, your zoas are glad they aren't zoa spiders

 

[YoungReefer00]

Should rephrase that, your zoas are glad they aren't zoa spiders

Hahaha yeah true! They seem to not bother my zoa's as far as I can tell so I am not too worried about my corals thank god

 

[vetteguy53081]

Hi everyone, I was just looking in my tank with a flashlight when I saw a couple of unknown isopods crawling around my Zoanthid coral, these isopods seemed to be eating away at the fragplug. I went to google to see if they were harmful since i’ve never seen them before and I only came across some very limited information. As far as I can tell now these isopods are either harmful Cirolanid’s or harmless Sphaeromatid’s. The isopods that I have in my tank have 3 “tails” instead of 2 that I see in pictures of Sphaeromatid’s, also they dont curl up into a ball as far as I can tell. Cirolanid’s are supposed to have big black eyes but these dont seem to have any.. does anybody know what I am dealing with here and if they are harmful?

Appears to be. The parasitic one - cirroland has visible antennas

 

[YoungReefer00]

Appears to be. The parasitic one - cirroland has visible antennas

Awesome, now I will be able to go to bed without any unnecessary stress the isopod's I have do not appear to have any visible antennas, what a relief.

 

[ISpeakForTheSeas]

The isopods that I have in my tank have 3 “tails” instead of 2 that I see in pictures of Sphaeromatid’s, also they dont curl up into a ball as far as I can tell.

Yeah, the three tails are two uropods and a long pleotelson - the elongated uropods are typical of male Sphaeromatids, but the long pleotelson (the middle tail) is unusual.

That said, I'm still confident your critter is a Sphaeromatid of some variety, as there are a ton of genera in the family, and at least some isopods from the family (such as a number of Cilicaea species) have the elongated pleotelson.

So, yeah, it's most likely a harmless/beneficial Sphaeromatid.