My cirolanid isopod battle

[NT Nano]

I am posting this because I found less info than I hoped on what to actually do, and I hope my experiences help others with these little monsters.
The saga begins with some fresh Florida live rock that I was using to recharge my tank after a major, life-ending-start-all-over-again crash. I had no fish at the time, and thus didn't have my QT tank set up. I thought I would be OK with careful inspection and close observation. As I was flushing the rock prior to putting it in my tank, I found 1 isopod, about 1 cm in length. Sadly, I didn't know what it was, nor did I know that this rock is somewhat notorious for having parasites. I thought they might be juvenile mantis shrimp (now know better). I got rid of it and placed the rock in my tank. A day later, one more of similar size feebly crawled out of the rock and I basted it out. No others appeared.

Fast forward 6 weeks.

I now have had stable params for 2 months, and have added fish and corals. One day I am staring at the tank, and find two little crustaceans hiding in the sand against the glass, in a shady corner. They are each about 5 mm (almost 1/4 inch) in length, and have wee beady eyes. They look like minis of what I found before, and an alarm goes off...

 

[NT Nano]

Saga continues...

Saga continues...

So now I do some major research. Among other things, this article http://reefkeeping.com/issues/2002-05/rs/ was very helpful in determining that they were likely cirolanid isopods.
Now, this is a big family, and not all are bad guys, so I still had some hope. Since learning that they are nocturnal feeders, I did a flashlight sleuthing job the next night. To my horror, there one of those little suckers was, latched firmly to the tail of one of my PJ cardinals.
Now it was war.
I read about catching all fish except for a sacrificial lamb, but my QT isn't big enough for all of my fish, nor are any of the fish "easy" to net if the sacrificial one did catch isopods for me, so I did the next best thing.
I fashioned a trap based on some research on wetwebmedia.com, consisting of a clear tube with fresh meat inside, and isopod-entangling filter fiber packed in each end. (See photo below). It didn't work, although a few did swim nearby, and perched on the glass where I was able to suck them up with a baster. These guys are super fast, making a net impractical.
Now what?

 

[NT Nano]

Success!

Success!

The next morning (before lights-on)I did manage to net a PJ with an isopod near his eye. I held him still with a wet paper towel and removed it with tweezers. I also observed several more isopods darting around the tank. As soon as lights came on, they went to ground, immediately disappearing into the sand and rocks, but the PJ gave me an idea...
I had read several places that they will attack anything in the tank at night, so to watch out if you put your hands in the tank. I thought, well, why not?

Yes, I used myself as bait. I slowly wafted my hand around the rock work, over the sand, through the water, wiggling my fingers enticingly, and yes, the little monsters attacked. They darted in so fast I usually did not see them coming, only feeling a little pressure and possibly a small sting when they latched on (WAY smaller than say, a mosquito bite). Once attached, they would stay there even when I raised my hand out of the water to pinch them off and put in my capture container.
Still more continued to perxh on the glass, often either at the water line, or just above the sand, and I was able to baste them out.
The first night I caught 26 of them using this method. The second night I caught 3 on my hand and 2 on the glass.
I didn't find any last night, and I have not seen any more on the fish.
According to the article in my first post, a female will have 10- 30 young, in which case I have caught an entire brood. I am now hoping that there is only one, and this is at an end, but of course many months of watchful waiting will follow!

 

[Sugar Magnolia]

While you definitely have some cirolanids in there, you also have some harmless sphaeromatid isopods in the above picture. The way to tell them apart is that cirolanids have very large eyes and cannot curl into a ball. Spaeromatids have much smaller eyes and can curl into a ball.

 

[NT Nano]

I beg to differ. They don't curl while in the tank, but once out of the water they do. All of these guys have visible black eyes, (you can't see some due to the angle, but they are definitely there) and all in the net were plucked off of my hand while actively sucking on me...pretty good evidence that they are active carnivores/parasites.
I have done a lot if research, and apparently the curling thing is not as cut and dried as you would think. I don't mean to sound like I am jumping on you, I just want folks to realize that isopod identification is complex, even for the experts. I carefully observed each of these guys, and they are all identical despite their post-mortem postures (They curl more after death too.)

 

[NT Nano]

Another big one

Another big one

Last night I caught a quick flash of motion in the moonlit tank, and tracked down this sucker. "She" is over 1/2 inch in length, and hopefully the source of the juveniles I have been catching (caught 2 more little guys last night too). While slightly bummed I am not surprised that this infestation was not solved in 3 nights of hunting... There are just too many hidey holes for that to happen. Still, I feel that I am making progress, and I plan to continue this method for now, rather than tear apart the whole tank.

I guess the big take away comes back to the basics QUARANTINE EVERYTHING! Almost every time I have cheated on this I have been burned. It is not worth it!

 

[olemiss reb]

Impressive collection method. I had cirolanids years back and never thought of using myself as bait. I ended up draining the tank and cooked all the rock.

 

[NT Nano]

I admit I feel a little crazy doing it this way, but it is all that works. Thankfully I was able to net the big one, because I bet that bite would actually hurt!

 

[alprazo]

Dimilin will take care of your problem.

 

[NT Nano]

Alprazo, what is your experience with Dimilin? From what I see it isn't reef safe, but all things are relative. I have a full complement of inverts (snails, crabs, urchin,)but I worry most about it nuking the feather duster as well as other beneficial amphipods, copepods, etc. It would be awesome to have a fall-back if things get out if hand!

 

[alprazo]

I have used it several times. It did not affect my hermits, snails, lobster and bivalves. It wiped out my amphipods, my intent for treating since I had a parasitic species. Will wipe your copepods too, but they are easy to replenish. Not sure about corals.

 

[NT Nano]

Thanks alprazo. I will keep it in mind, but probably won't risk my corals. I haven't seen any more isopods since catching big mama. I expect to find a few stragglers, but fingers are crossed.

 

[e048]

Be careful using yourself as bait you may catch something although highly improbable it can happen

 

[NT Nano]

Thanks e048. Thought of this too and decided to risk it. Also, obviously this technique wouldn't work well in a tank with anything aggressive, including mantis or pistol shrimps. Maybe they would eat the cirolanids

 

[NT Nano]

Still Fishing

Still Fishing

I took a few days away for some travelling, and hadn't seen any isopods since my return, but last night I spotted one on a rock. I basted it up, then went fishing with my hand and got one more biter. No others seen. These guys were slightly larger (about 2 mm) than the previous babies, and starting to turn from pure white to grey. I am assuming they are maturing from the same hatch as my previous catches. I have not observed any more adults or tiny white youngsters, so I am still hopeful that I can round up the last few stragglers and end this before another reproduction cycle begins. Fingers crossed!

Another takeaway from this experience is take the time to observe your tank at night! Not only is it fun to see the polyp-and-tentacle-extending, amazing transformations the corals undergo, but I can guarantee you will see something you never knew was in your tank... Bristle worms, amphipods, isopods, brittle stars, etc. to name a few.
Despite actually pulling a cirolanid off of a fish with tweezers, not to mention multiple observations of them feeding on my fish, I have yet to observe a lesion of any kind on the fish. No ulcers, wounds, missing scales, etc. In other words, I would have no idea that my fish had these nocturnal predators bothering them if I had not seen it with my own eyes.