critter id

I have these little guys all along the glass in the sandbed. Have a few in the sump as well. They appear to make their own little cocoon type of thing when there is no sand available. Spotted a couple that are much darker in color, almost black, but couldn't quite get an angle on them to record.

I noticed this little orange-thing while checking out my tank today, thought it was a sponge at first but when I came back to look at it later it was moving and had revealed two little antennas! It only has two colours, orange that fades into a darker orange/brown towards the body, has a clam...

These clear "tube" critters have almost completely taken over the rear chamber of my nano AIO. They're growing and attaching themselves to the glass, heater and temp probes. I've also started to notice them growing on the rock in the tank as well. They seem to soft tissue and not hard, they also...

Never seen one quite like it anyone can ID it came in on live rock rubble it moves , it has two small holes on each end - it is soft and squishy like a slug / snail / anemone and I have seen it squirt once or twice - looking to figure what it is if NPS or a pest or a fish eater Also anyone...

Curious what these are? They look oval shaped and smaller than a grain of rice. Look brownish and move around the glass. Have a V shaped end to the body. Mainly on the glass but probably on the overflow and elsewhere. A good amount of them. Tank has been setup with live sand and live rock from...

I just cleaned a bunch of algae out of my sump and found these critters that look like tiny smooth (no hair or bristles that I can see) caterpillars. I’ve never seen these. In the photos they look flat, but they aren’t. They are nice and chunky. Any help on an ID is appreciated!

Anyone know what these are? They are tiny worm like looking things. I have an idea of what they may be but not positive. Found them inside the skeleton of a dead alveopora… removed it from the tank to detach it from the frag plug it’s on. I try to leave behind coral skeletons in my tank hoping...

Took a sample from my sump and saw this under the microscope. They are clear and pretty fast moving. Any idea what they could be? I have large cell dino in the display. Thanks

Does anyone have an idea of what this is? It’s about 1cm long and moves very fast. Some type of flatworm? I recently received some TBS rubble for my sump.. just want to make sure this isn’t a bad critter.

I just saw a relatively big worm come out from my rock and grab the leftover brine shrimp and then back out to the rock… should I be worried? What is this?

These popped up this morning or well I noticed them this morning, first thought was they are micro brittle stars but also could be some type of worm. I have only a few, fish, common/caribean star, snails, hermits, cleaner shrimp, pistol shrimp. I’ve only used a small piece of live rock from my...

Anyone know what these tiny bug/shrimp looking things are? They are all over this rock and under the coral. Are they good for the tank or are they about to kill everything in sight? Thank you!

Hello everyone, I recently added my first cuc and corals to my tank on the 6th of June (List below). I am running the tank fallow currently and realized that some of the inhabitants need something to eat so I fed some algae wafers, frozen mysis and baby brine shrimp. Emerald crabs Astrae...

Brought a handful of ocean sand to seed my new small 5 Gallon tank. Intentional. Wanted to experiment in a small tank with ocean sand/seeding. Saw these guys running around. Does anyone know what these are? I am planning to set up the tank as an exclusive nem tank. So in essence they will be...

Found this crawling around in my sea urchin. It was flat and looked like a big flatworm. Dropped a bunch of eggs when I dipped the urchin in fresh water to knock it off. Sorry no better pictures.

Someone please help me identify this worm, I’m scared it may be a pest

Hello,I found these hitchhikers that came out of my live rock. The first one is some sort of strings that are in between two rocks. The second one is one string coming out of this tube on a rock. And the third one is a weird slug looking thing that was on the glass. Any ideas as to what these...

I recently added some ocean aquacultured live rock to my tanks that came with all sorts of cool sponges tunicates etc. Added a really nice piece to my macro tank. I’ve noticed a few bristle worms crawling around when the lights go out which I don’t mind. I was checking for other critters last...

Just found this in my tank don’t know if it’s bad? Hard to get a good view of it, if anyone could help that would be great, must be some kind of snail but I only have conches in my tank and is not like them at all

What is this on my lobo. Looks like a barnacle but it gets smaller when I spook it.

Hi I have noticed these strange critters. Almost look like little flatworms but move like copepods they are dark red towards black to look at under blue lights. I think they are causing some tissue recession at the base of my acros and my candy cane coral? Or they may not be a pest and the...

Hello, A couple of months ago I happened across a couple of snails entangled and rolling around the floor of my aquarium. I thought to myself that those snails really like or dislike each other. Turns out it was the former and now I have hundreds of little snails sliding rampart around my...

Hello, need help id the small critter I found in the tank. It looks like some kind slug, with reddish color. Reef safe or not?

I found this little creature crawling on my glass at night, and I believe they’re flatworms. Can anyone help ID this? Or at least tell if they’re harmful or not? It looks transparent/white with black dots on them. Doesn’t look like brown flatworm unless it’s a baby.

cool video of my 1.5 year old mandarin eating some kind of worm from the rocks … what do you think it is ?