Unknown Critters... Hopefully Harmless...

[Kylepoma12]

I recently noticed that a frag of green mdntipora had a small area where the flesh was gone and the skeleton was exposed. It had soon before i noticed this fallen from it's spot, so I thought that it had possibly been damaged and the flesh had simply fallen off. I kept an eye on it, and a week later I noticed that the area of exposed skeleton was a bit bigger, so I got worried and took it out of the tank to look for any pests. I gave it a quick freshwater dip, and some small, what looked like worms fell off (1st video down below). I did some research but couldn't identify them. The closest thing they looked like to me was AEFW(acropora eating flatworms). I spoke with my LFS, and they didn't think that they were worms, or anything to worry about. They thought that my mdntipora frag had possibly gotten a bacterial infection of some kind, and that it was munching on the flesh. The rest of the frag was healthy and growing, so they said to give it a dip in 2LF Revive and just to keep an eye on it. I was still a little nervous since the guys at my LFS aren't exactly scientists, they're more along the line of fish bros, but I didn't really know what else I could do so I waited and watched. The montipora frag promptly died the next day, and I can only think this happened because it didn't like the freshwater dip in RODI water. I have read some opinions that say never freshwater dip, it kills corals, and some that say do it. I have never had problems with freshwater dips personally, so it was a surprise that it died.

Anyways, that was about a week ago. Tonight I was walking by the tank after the lights went off and checking it out with the flashlight from my iPhone and I noticed some critters on another frag that looked like small silverfish crawling on it. I think the frag is a blastomussa coral, but not 100% sure. I pulled it out in a cup of tank water to get a closer look, and I found about 5-6 of the silverfish looking critters, as well as a few of the critters that I had found on my montipora frag previously. The frag is growing really well, and I haven't noticed any problem areas or issues, but the 2 different kinds of critters do worry me, and I'd like to be sure what they are and if they will cause me any problems. Any help in identifying them would be very much appreciated. Thanks!

Video of the critters I found on my montipora frag:


Video of the critters I found on my blasto frag:

 

[Kylepoma12]

Here are some pics of them. Also, don't know if this helps in identifying what they are, but I discovered that if you flush them down the drain after getting them off of your frags it gets rid of them ;-)

 

[Maritimer]

Looks like you've got some munnid isopods, and a few "sand skaters". They're good to have around, as they help (in a small way, of course!) with cleanup, do no harm, and make tasty, healthy snacks for fish.

~Bruce

 

[Kylepoma12]

Awesome, what a relief!!! Thank you so much for your assessment and reply @Maritimer !

 

[Maritimer]

You're welcome, Kylepoma12!

~B.