Cirolanid isopods? ID?

Brooks Allman · Nov 21, 2023

I bought some Live Rock from Tampa Bay Saltwater and I noticed an isopod dead at the bottom of the shipping box so I decided to set a trap and see if I had the cirolanid isopods that seem pretty common with Florida aquacultured rock.

I caught about 10 the first night and have caught 5-8 from tiny to large every night since.

Can someone ID the photo and confirm it is one of the fish predators/parasites?

I have all the rock isolated in a fish less QT in my basement that is intended to be the sump.

Side note to anyone trying to get rid of these.

There are mason jar attachments on Amazon to catch fruit flys. These are very effective. I also had some frozen mahi from a Florida trip recently and these seem to work better than the frozen stinky water shrimp. I just let them thaw from frozen and find more in those traps. I will probably set 5 traps a night to really try and remove them all.

Seems like a major pia to remove them for good but I don’t want to toss $1,000 of live rock ‍

.

Jay Hemdal · Nov 21, 2023

Those do look like Cirolanids. As you mentioned, they are common with fresh live rock. IMO the benefits of fresh rock outweigh the issue with these - as long as you trap them out.

They are not parasites in the strict sense of the word, more like "micro predators".

Jay

Brooks Allman · Nov 21, 2023

Attached is the photo of the fruit fly trap. I replaced the metal lid with a plastic one. About $25 all in on Amazon.

EeyoreIsMySpiritAnimal · Nov 21, 2023

Does this help?

How to tell the difference between "good" and "bad" Isopods (CIROLANID VERSES SPHAEROMATID ISOPODS)

CIROLANID VERSES SPHAEROMATID ISOPODS. When you know what your looking for, telling the difference between a Cirolanid (bad) versus a Sphaeromatid (good) becomes a lot easier. It's all in the eyes..... The eyes of the Cirolanid are generally closer together and towards the front of the head...

www.reef2reef.com

EeyoreIsMySpiritAnimal · Nov 21, 2023

Jay Hemdal said:
Those do look like Cirolanids. As you mentioned, they are common with fresh live rock. IMO the benefits of fresh rock outweigh the issue with these - as long as you trap them out.

They are not parasites in the strict sense of the word, more like "micro predators".

Jay

To me, the eyes seem too far apart to be Cirolanids...
@Brooks Allman , do they curl up at all?

Brooks Allman · Nov 21, 2023

EeyoreIsMySpiritAnimal said:
To me, the eyes seem too far apart to be Cirolanids...
@Brooks Allman , do they curl up at all?

Not all the way but maybe like a half curl.

EeyoreIsMySpiritAnimal · Nov 21, 2023

@JoJosReef , any ideas?

Jay Hemdal · Nov 22, 2023

EeyoreIsMySpiritAnimal said:
To me, the eyes seem too far apart to be Cirolanids...
@Brooks Allman , do they curl up at all?

The tail doesn't look right to be a Sphaeromatid, to me anyway. I lump Cirolanids in with the Aegids, and within the whole group, some are micro predators and some only scavengers. However, the one common way the micro predator species get into aquariums is through fresh live rock from the Gulf of Mexico, so I think trapping would be warranted.

Here is a link to Ron Shimek's very good article on the group:

https://www.reefkeeping.com/issues/2002-05/rs/index.php

Jay

george9 · Nov 22, 2023

I received just 8lbs of TBS rock about 2 weeks ago and this morning noticed a cirolanid on my Biota yellow tang. Not sure what I’m going to do yet but yours look almost identical to mine, and I’m pretty sure mine it is a cirolanid because it’s latched onto the poor fish. Kind of irritated about it, always hear nothing but good things about ocean live rock (minus the occasional gorilla crab issue) but if I knew they could come with bugs that suck blood out of my fish I wouldn't have taken the chance lol

Not a knock at TBS by any means as they have basically no control over it. Just a risk with all live rock I suppose.

TBS says this nuisance is temporary as they will not reproduce in aquariums and they will not kill fish. Not sure how accurate that is
but they have a page here - https://tbsaltwater.com/hitchhikers/isopod-cirolanid/

JoJosReef · Nov 22, 2023

To me look like spheromatid isopods. I have those. Their eyes are farther apart and less "sinister".

Spheromatid found dead in overflow:

Cirolanid from google images

I spent a lot of time stressing about these guy. If you have fish and find one attached to the fish, that's pretty positive for a cirolanid.

Also check out lionfish lair's post

How to tell the difference between "good" and "bad" Isopods (CIROLANID VERSES SPHAEROMATID ISOPODS)

CIROLANID VERSES SPHAEROMATID ISOPODS. When you know what your looking for, telling the difference between a Cirolanid (bad) versus a Sphaeromatid (good) becomes a lot easier. It's all in the eyes..... The eyes of the Cirolanid are generally closer together and towards the front of the head...

www.reef2reef.com

Jay Hemdal · Nov 22, 2023

george9 said:
I received just 8lbs of TBS rock about 2 weeks ago and this morning noticed a cirolanid on my Biota yellow tang. Not sure what I’m going to do yet but yours look almost identical to mine, and I’m pretty sure mine it is a cirolanid because it’s latched onto the poor fish. Kind of irritated about it, always hear nothing but good things about ocean live rock (minus the occasional gorilla crab issue) but if I knew they could come with bugs that suck blood out of my fish I wouldn't have taken the chance lol

Not a knock at TBS by any means as they have basically no control over it. Just a risk with all live rock I suppose.

TBS says this nuisance is temporary as they will not reproduce in aquariums and they will not kill fish. Not sure how accurate that is
but they have a page here - https://tbsaltwater.com/hitchhikers/isopod-cirolanid/

Yes, the old truism is - "fish parasites are found on fish", so that is most certainly a micro predator. Now, can these develop long term populations in aquariums, or do they die out? I'm not certain. I know of a case in a public aquarium in Europe where cirolanids formed a long term population that actually got worse over time, not sure what species they had though. In home aquariums, people trap them and the problem seems to go away - is that due to the trapping, or due to the population just dying out on its own over time? IDK for sure.

jay

JoJosReef · Nov 22, 2023

EeyoreIsMySpiritAnimal said:
To me, the eyes seem too far apart to be Cirolanids...
@Brooks Allman , do they curl up at all?

Brooks Allman said:
Not all the way but maybe like a half curl.

I understand if there is any curling it's unlikely to be cirolanid. I have to read more about Aegids, but I've found it hard to ID by tail structure outside of the tank. Sometimes curled under like in my photos and sometimes it's just a bit too transparent.

george9 · Nov 22, 2023

I just bought a planaria trap from Amazon that apparently works for these guys (https://humble.fish/community/index.php?threads/sphaeromatid-or-cirolanid-isopod.16607/page-3)

Here’s the trap - 2 Pack Clear Glass Planaria Trap Catch Trap Aquarium Cleaning Supply for Dwarf Shrimp Cherry Shrimp Crystal Red Shrimp (3 Holes) https://a.co/d/4uwsO1Q

It arrives Saturday, will see if it works!

JoJosReef · Nov 22, 2023

george9 said:
I just bought a planaria trap from Amazon that apparently works for these guys (https://humble.fish/community/index.php?threads/sphaeromatid-or-cirolanid-isopod.16607/page-3)

Here’s the trap - 2 Pack Clear Glass Planaria Trap Catch Trap Aquarium Cleaning Supply for Dwarf Shrimp Cherry Shrimp Crystal Red Shrimp (3 Holes) https://a.co/d/4uwsO1Q

It arrives Saturday, will see if it works!

Also look up the stinky water trap method and the adaptation to it.

Basically let a shrimp rot in a bottle trap and introduce it at night, let the cirolanods get in and get them before they find a way out.

Adaptation was that they just used the stinky water, turkey baster shot it against the glass at night with a red flashlight on the tank, watched the cirolanids rush to the glass and then suck them up with the baster--I understood that the "yield" was better with this active approach.

Sorry, I don't have links handy!

george9 · Nov 22, 2023

JoJosReef said:
Also look up the stinky water trap method and the adaptation to it.

Basically let a shrimp rot in a bottle trap and introduce it at night, let the cirolanods get in and get them before they find a way out.

Adaptation was that they just used the stinky water, turkey baster shot it against the glass at night with a red flashlight on the tank, watched the cirolanids rush to the glass and then suck them up with the baster--I understood that the "yield" was better with this active approach.

Sorry, I don't have links handy!

I’ve seen that and was going to try to make one with a Coke bottle but not quite sure exactly how to go about submerging it.

Do I leave stinky shrimp water in the trap, and then slowly submerge it letting it fill with tank water as I place it on the sand? I’d imagine the stinky water would just leak out of the hole and not quite stay inside the trap. I was thinking about putting larger chunks of frozen food at the bottom and submerging it overnight, but will try it with these glass planaria traps first. Am I misunderstanding how it works with the bottle? Just don’t see how the “bait” stinky water will stay inside the bottle once it’s fully submerged.

JoJosReef · Nov 22, 2023

george9 said:
I’ve seen that and was going to try to make one with a Coke bottle but not quite sure exactly how to go about submerging it.

Do I leave stinky shrimp water in the trap, and then slowly submerge it letting it fill with tank water as I place it on the sand? I’d imagine the stinky water would just leak out of the hole and not quite stay inside the trap. I was thinking about putting larger chunks of frozen food at the bottom and submerging it overnight, but will try it with these glass planaria traps first. Am I misunderstanding how it works with the bottle? Just don’t see how the “bait” stinky water will stay inside the bottle once it’s fully submerged.

I didn't have any success with the stinky bottle and before trying the adapted version caught some of the Spheromatids and decided to leave it there. I still occasionally see them scuttle around the sand bed but never seen one on a fish.

I'd stick to the instructions from the thread on R2R and maybe ask for advice on a new thread.

Tavero · Dec 15, 2023

Stinky water does nothing. I was feeding frozen food made out of artemia and fish puree and one of these bugger went straight for my hand to bite it. Didn't care for the frozen food at all.

EeyoreIsMySpiritAnimal · Dec 15, 2023

Tavero said:
Stinky water does nothing. I was feeding frozen food made out of artemia and fish puree and one of these bugger went straight for my hand to bite it. Didn't care for the frozen food at all.

I think you've stumbled on a new way to catch them!!