hitchhiker id

Hi! Does anyone know what these are? Friend or foe? They've started popping up all over 2 pieces of live rock that came from someone's tank breakdown. They appear to be attached and aren't moving around. The fan looking end doesn't retract or spook like a feather duster worm. The fan looking end...

What that heck is on my urchin?? He has been carrying it around for almost a week and it has not moved. Its fluorescent and only appears yellow under blue light.

Hello everyone and welcome to this little microscopy thread! Many hobbyists stumble upon microscopes once they are dealing with a pest they can't properly identify any other way. Besides their obvious usefulness when dealing with a problem, microscopes grant access to a whole new world many...

I went on a trip to Vegas about a little over a month ago. Brought home a new torch. Dipped it, put it on a new plug, and put it in the tank. A few weeks later, I noticed these on the glass (I'm assuming this torch is what they rode in on). They're VERY small. About the size of a 0.7 or 0.5...

This little guy was in a bag of hermits I ordered. He's about 1-2cm across. His front claws are pretty long comparatively and very symetrical. Maybe a porcelain crab? Does not look like the mithrax that came in a separate bag.

Hammer coral has a clear with orange spotted growth that looks almost like a fungus and what appears to be circular orange sacs of some sort that are getting larger and spreading out. Is in a semi spiral pattern on Skeleton that's expanding. It seemingly is causing flesh recession. I'm verifying...

I’m working on turning my nano reef into a macroalgae tank for dwarf seahorses. It’s been up for a year now and these little things have been in there for about 8 months, basically since i added the one extra piece of rock that they’re on. There’s only a few of them on that one rock and none of...

I've only just noticed this... thing after a month of the coral being introduced to my tank. Tried figuring out what it is but I'm totally stumped. It has hairs that reflect light with a rainbow sheen as well at 3 tentacles coming from its face. Has a calcified tunnel that has bored through the...

This came on a zoa rock, zoas arent open atm so its hard to compare. I suspect its some sort of anemone, might be a majano but there are so many types of majanos. Wondering what it might be.

I'm currently cycling a mixture of live and dry rock to add to my display tank; after a year + I'm beginning to think I need some more live filtration. Currently, there's nothing but Marco rock in the tank. As I was measuring the chems today, I notice the guy in the picture hanging out on the...

Found this guy while doing maintenance today, doing so research I believe that it's a Sphaeromatid isopod, can anyone confirm if that's correct and he's reef safe?

Good or bad?

So I have a piece of now dead coral I dont want to throw it as it has a bunch of stuff on it, feather dusters, and a turnicate. Today while feeding my coral and having all pumps off is notice this black and white worm looking thing moving. Any idea of what this is??

A few various sizes of these curious and very energetic, wriggly guys came in my live sand today and I was able to grab a couple with tweezers and throw them in a bucket. Was tough to focus the video, looks to me like it might be lancelets. Could anyone confirm...

Noticed these weird purple growths on my zoa and duncan frag plugs. Can anyone tell me what this is?

Recently discovered two of these guys in my tank. Must've come in on a frag (despite dipping) or maybe a snail. Kinda looks like a ball anemone but I can't tell. The two I have are in darker areas and mostly clear with a little color under blues. Tentacles radiate evenly around the mouth plate...

Hello, I need help to id this hitchhiker! I bought a colony of discosoma mushrooms a while back and I notice colony of polyp-like hitchhiker beside the mushrooms. Some of the mushrooms that close to the polyps kinda shrunken.

Finding hitchhikers (benign ones especially) is actually one of my favorite things about reef-keeping! And today I noticed a new friend in my 1.5 gallon that I most definitely did not add. It’s a beautiful little crab, but not particularly active— I’ve never actually seen it move, just sort of...

Hey guys Everything’s been going so well in the tank and everyone seems to be happy! Just one small question…I have 2 red legged hermits that do occasionally latch onto each other n then let go after a few minutes, I tend to leave them to it as there are plenty of shells for them to change...

Hello! Rescued a sizeable pectinia that had a couple pests on it. It had a large vermitid that I glued over, a majano which I injected with lemon juice and covered with CA glue. There is a red sponge which I hope lives! BUT...What's in the picture? It looks completely different from the other...

I've tried to ID these guys, but I swear they look like 10 different worms when I tried comparing pictures. This is through one of those phone connected microscopes, as the worms were crawling through the sand. They're about 0.5in long, super thin, and white to the naked eye.

I went over to look at my tank tonight and saw a snake like creature in my live rock when I tried to take a picture of him he retracted into the live rock so in the photo I just have part of him.

I got this elephant ear mushroom a couple months ago. It's usually hand size but today it's been shriveled up and I noticed these on the rock that has been hiding under the coral. Seeing if I could get an ID on them. Good or bad?

Happy New Year to All! I introduced my first corals last week and now find a number of mystery guests on my glass and possibly in the water column. Can anyone tell me what these are?

Really curious what these are. I've searched the internet on and off endlessly over the past few months to no avail. One or two has turned to a couple dozen and I'm wondering whether I need to take action. They haven't died off like pineapple sponges usually do. They look like a cross between a...