Sphaeromatid Isopod roly-poly invasion

[Lyss]

I've had a bunch of coral frags stuck in the sand for the longest and finally got around to moving the last remaining ones to the rocks. Usually when I lift them out of the sand the plugs have a little bit of detritus on them and maybe an amphipod or two, but they're pretty clean. This time, I pulled a bunch of frags out of the sand and there were these little moving blobs on them -- I was thinking they were a type of flatworm, but after looking through a jewelers loupe, they are clearly some sort of cute-ish roly-poly Sphaeromatid isopods. They have pretty cool tan and black patterns on them, too. I assumed they must be some sort of detrivore since they where clearly on the undersides of plugs and where the plugs were wedged into the sand, and none of the corals look bothered. Creepy nonetheless b/c of the sheer numbers of them.

I was wondering if anyone knows much about these, and if their populations are likely to dwindle with time. I must have had some survive the dipping process on the newer corals I added in April, is my thinking.

I guess I can always do a gravel vac on the top layer of sand to remove a bunch, like I do to knock down the amphipod population now and then. Lately I've seen both my clownfish hunting stuff in the sand pretty much all day into the evening, so I know there's lots of stuff in there, whether it's amphipods, or these isopods, or whatever.

 

[EeyoreIsMySpiritAnimal]

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

 

[Lyss]

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

Thank you but I read through that before posting this and it doesn’t answer my question.

I have an ID, but am wanting to know more about them and if their populations will naturally dwindle, or if I should actively remove some.

 

[Lyss]

Bumping this. Isn’t there anyone with more info or direct experience on these? I’m trying to figure out if it’s the type of situation where populations can explode, or more like amphipods where they wax and wane naturally and it’s no serious worry to do anything to knock down the population.

They almost look like chitons w/their pattern, but under a jeweler’s loupe it’s clear they are a type of Sphaeromatid isopods, by the look of them and the way they roll.

 

[damsels are not mean]

Hard to know about that species specifically, but you'd think if there were a species that was problematic like that you'd hear about it. Given that nobody mentions them they probably remain unnoticed in a lot of people's sand.

 

[Lyss]

Hard to know about that species specifically, but you'd think if there were a species that was problematic like that you'd hear about it. Given that nobody mentions them they probably remain unnoticed in a lot of people's sand.

Yeah, I guess I'm just not gonna worry about it. They're not doing any harm, it's just unsettling to pull a frag plug and find them all over the bottom. Honestly tho IDK why -- I find amphipods in every piece of ulva I pull out, and on every frag as well but am not bothered by them. Prob b/c these look like bugs more than the amphipods do, ha. I'll just do a little bit of gravel vac next water change to get rid of a bunch.

 

[JoJosReef]

Did you find out anything more about these isopods, Lyss? I suppose the biggest question is, are they exclusively detritivores or can they progress to munching on living corals or parasitizing fish?

I just found a dried up one outside my tank today and think they are sphaeromatids (hoping at least). I also pulled up a dead acro frag and found a bunch of smaller isopods under the plug.