Ok I see sooooo many “WHAT IS THIS” posts. I decided to make a thread where people can come look BEFORE they post. SO I hope this helps someone. Also help pass this along to anyone who is looking for an ID. Its taken me a while but let me know if I forgot anything I will add it. Its going to be very basic with a brief description and with pictures that will be under each description. The goals of this is not to provide information to get rid of the hitchhikers, or any detailed info but to simply ID them and then leave it up to you to search and find more information on removal of critters and algae.

I will start with the harmless critters:

Amphipods, Copepods, Good Isopods and Just Bugs: Pics in that order. HARMLESS
Now there are some 5,000 species so I will list the most common ones. These are all harmless, you will see them on the glass rocks and your hand if you leave it in there long enough, These are the most common species. Pictures in this order, Amphipods, Copepods, Isopods.


Mysis Shrimp: HARMLESS
You will probably only get a short glimpse they are VERY fast lol. You will almost always see them in your fuge, sump or back in the LR at night. At night with a flashlight their eyes will glow. They also make great tasty treats for your fish so as they reproduce toss them in the display!


Bristle Worms: HARMLESS
Jury is out on these, but IMO if they stay small they are harmless and actually keep your sand nice and clean. There are also large other species that can be very damaging to a reef tank, they will be listed later.


Spirorbis: HARMLESS
Tiny while calcareous worms, that mostly will develop in the dark areas. Filter feeders and a sign your tank is doing well, very common.


Feather Duster Worms: HARMLESS
Again like pods there are too many to list here however they are harmless filter feeders, and some can be BEAUTIFUL! I have some red spotted ones and some pretty frilly white ones.


Stomatellas: HARMLESS
Probably the most common “WHATS THAT!?!?!” Looks like a snail with ½ a shell. You’ve got to love these guys they are SOO cute! If I could buy them at my LFS I would. GREAT algae grazers, and have been known to even eat cyano.


Collonista Snails: HARMLESS
Often mistaken as sundial snails, these are harmless grazers. They multiply very quickly and while they are out in the daytime, you will usually see tons on the glass at night.

thanks tuidizzle for that second pic.

Brachiopods: HARMLESS
Hard to find an ID on these, but they look like little clams (rounded edges sometimes rippled) imbedded in your rocks. They are bivalves and are on a hinge and look similar to clams, and mussels. They are filter feeders.


Asteriniid stars: HARMLESS
Occasionally, some populations of these asterinids have been reported by aquarists to eat either soft corals or stony corals. These coral-eating forms, perhaps different species, seem to be really uncommon, constituting less than five percent of the various populations. So I will list them here but observe with caution.


Foraminiferans: HARMLESS
These are really interesting things. Often miss labeled as corals, or sponges these animals actually are one of the oldest forms of life on Earth. Pretty amazing and very common in our tanks. I see those white looking disk ones all the time, and the red ones are really beautiful.


Spaghetti worm and Hair Worms: HARMLESS
While these are considered harmless I have noticed they can really bug corals especially zoas so much to the point the corals will not open. They scavenge the sand and rocks as far as they can reach. Pretty strong too I have seen mine reel in large pellet food. Kinda cool lol.
Hair Worms looks very similar only they have just 2 feeding arms.


Limpets: HARMLESS
Harmless little guys, and pretty cute too. Algae grazers that usually come in on the rock. There are lots of species but most have a pointed shell, and pretty easy id.


Sponges: HARMLESS
Ok so here is another "WHATS THIS" that I see all the time. There are so many color variations and different textures but here are a few common ones. Yellow, white, brown, tan, cream, red, orange and blue and pink are all ones I have seen. They are easy to ID by the fact that they always have a tube like structure, it may be very short for an exhale, they often have a web looking texture. They are filter feeders and a great thing to have.

Tunicates: HARMLESS
These can be tricky to ID. Some look very much like sponges. Most are round tall cylinders with 2 vents inhale and exhale. Often clear but also white and on some occasions blue, red and other beautiful colors.


Peanut Worms: HARMLESS
Ugly little guys, great for cleaning up the tank thou, eating detritus and various in sand materials. Mainly nocturnal.

Photos courtesy of C est ma. These are the feeding tubes, likely to see them during the day.


Chitons: HARMLESS
Hard as rocks, and look like rocks too. Almost looks like flat potato bug.


Vermetid: HARMLESS
Typically harmful if nothing is around. I have noticed that these things (I have some big ones) when they create their slime trail it really bugs all your corals. They will keep zoas closed up completely and really irritate any others to the point that it will kill the coral. I have personally even lost colonies because of these. So just watch with caution.


And now the harmful critters:

Nudibranchs and their Eggs: HARMFUL
There are MANY species, however a few common are the Zoanthid Nudi, the Montipora Nudi, and Soft coral Nudi Pictured in that order below. Lately it seems like almost every colony of Zoas is infected. These nudis are usually very hard to spot and blend in with their food (your corals) Some can be removed by dipping others you just got to find and pry them off. Egg masses are hard to spot, and vary depending on species.



Aptasia & Mejano: HARMFUL
These are a big time PITA. They move around pop up out of nowhere. They can sting corals and if big enough eat small gobies and such. There are different kinds and colors, and all hard to kill. Aptasia are stronger than Mejanos but still can harm corals. Some people like Mejanos lol and actually buy them… they are kinda pretty lol.


Creoland Isopod: HARMFUL
Like ticks on dogs they will slowly feed on your fish. Removal can be tricky but can be done. You defiantly want these out of your tank.

Zoanthid Spiders: HARMFUL
Nasty buggers. If you have a sick colony, that’s not opening look for these guys. Manually remove any you can find and QT. They typically are very small.


Red Bugs: HARMFUL
Found on SPS, and VERY tiny. Hard to see but will have a orange-ish color and will look like little dots. I put these in harmful, but I think most hobbyists have these in their tank. Seems impossible even with proper dipping methods to kill them all.


Sundial Snail: HARMFUL
Harmful to zoanthids. Usually easy to spot and remove, however babies can be pretty tiny.


Flatworms: (Not all are bad, clear ones are harmless) HARMFUL
Usually a rusty red color (clear flatworms are harmless and algae grazers) and can over take a tank easily. Removal is tricky, as they can release toxins when killed, using a air line tube, suctioning these out is the best method.


Pistol and Mantis Shrimp: HARMFUL
Pretty harmless to corals and such, but can spit your finger right open. Can also harm and kill fish, as well as CUC members. These both come in a huge variety of colors and sizes, but you will always know they are there by the loud snapping noise.


Rock Crabs: HARMFUL
These are hard to spot and usually come out at night, They will eat anything they can catch including small fish and CUC members if they get hungry enough. They can also grow pretty large at times. A tell tale sign you have one or more is that you will see the shed, especially the large claw shed.


Fire Worms: HARMFUL
Nasty critters. These will feed on your corals and inflict a painful sting if touched. Sometimes fire worms can be hard to distinguish from common bristle worms.

Algae and Plants

Cyano Bacteria:
Slimy looking algae usually dark red. This is a bad algae and can take over a tank.


Diatoms:
Looks like a brown dust, sometimes a orange-rust color dusting over sand and rocks. This is COMMON while your tank is new. Not harmful and will usually go away on its own.


Dinoflagelates:
I have seen this somewhat often lately on NR. it’s a more rare “algae” and like cyano its not really an algae at all. It sometimes looks like diatoms, with a rust color, but usually is more stringy and usually (not always) grows bubbles.
More info here.
http://www.geo.ucalgary.ca/~macrae/palynol...lagellates.html


Green Hair Algae:
Probably the most common algae. Can spread over a tank quickly.


Bubble Algae:
Another pest algae. Usually wait until it gets bigger then twist off. Some people like the way they look lol.


Macro Species:
There are many different species: Please see this site for more info:


Here is a site with many different species of macro.
http://images.google.com/imgres?imgurl=htt...l%3Den%26sa%3DN

Coralline Species:
Comes in many colors and varieties. Most common is a nice purple color. Also in greens, whites, pinks and my favorite teal. This is a good algae.



HERMITS!!! This site is not in english but it gives the species names of TONS OF HERMITS! Its a great site! Thank you jaidexl for the link!!!!
http://www.recif.be/article/hermit.htm

PLEASE NOTE:
More information of almost all these critters can be found here:
http://www.reefkeeping.com/issues/subject/invertebrates.php or www.wetwebmedia.com or www.melvesreef.com I claim no pictures as my own, all were found on their respective sites.

WHEW, ok thats all I have for now. I think I covered most of the comon hitchikers. Sorry I had to do it in multiple posts, and I have an email out to CM about making this easier to use with a sticky. If there is something you would like to add please shoot me a pm and let me know. THANKS and hope you found this useful.

That was awesome!! It helped me tons and would've helped me tons if I read it first before asking!!!


This SO needs a sticky.

good job HC! very useful for noobs and olds alike!

p.s. if anyone in socal has majanos they're trying to get rid of and can get them out, bring them to meee!

Good deal! This is meant to be a very quick refrence, so that you can ID the critter and go on searching for more info. If people have additional personal pics of a critter thats listed or not listed please feel free to add it, better yet send it to me and I will see if I can insert it into the first 3 posts with the rest.

C es ma, made a good point, peanut worms while at night they may look like the pic above during the day you may just see a little trunk sticking out of the rock. This is a perfect chance to add your pics, they will be helpfull for anyone. After all, no way I could get pics and descriptions of every weird critter that pops up lol. I have been in the hobby for a long time but until this I didnt know the name of those little white spirals and now I know their called Spiriobs. Thanks again all and glad this is helpful!!

Really good post. It should be a sticky in the beginner section.

Dizam! Glad someone finally got around to doing this.

^^^
and in the id section too

some one put alot of time in this lol great work!!!!!!!!!!!!!

YEA we got a sticky!!! THANKS ALL glad you like it!!

What do I got here?

First one kinda looks like a white spiral, with a feather duster thing coming out of it. There are THOUSANDS of them in my tank, on the glass, and all over the rock. And I am not joking, they are EVERYWHERE! From the pics above they look like Spirorbis, but the feather duster part doesent look quite the same... yet the biggest one is only the size of a pinpoint.

2nd ones, are almost microscopic. Some with a pink and some with transparent bodies, they have 4 arms that look like a thread of spit, some have 5 arms. Look like super tiny star fish.

thanks for your hard work...great post helfrich's chick!!

Thanks BIG time for this Sticky

I almost asked "What is this" but after reading this fabulous article I got the answer;

Chitons: HARMLESS, cute little creature IMO.
I can add one thing about them;

Its been about two month now since I started this nano, and I have noticed this "shell" on a living rock.
It didn't move for 2 moth now and I was thinking it must be some kind of fossilized animal...BUT then yesterday it moved!!!
I was scratching my head for a while .... did this critter hibernate for a while...??? I mean this rock comes from Fiji... well something must have trigered this lil fellow to take action

I am glad it is harmless, kind a cute looking.



Thanks once again!
Kind regards, Dusko.

Awesome! I am so glad this thread is actually helping! Dusko I love chitons. They are really interesting animals. I had one that was over 2 inches long in my first tank, it was a 125. Same as you I knew it was something and not rock, just sat there for months then one day he was on the move. Very cool critters.

Tod, your first ones do sound like Spirobs, they usually do have a feather coming out which is their feding aparatus.
The second ones your talking about sound very much like a form of Hydroid. Hydroids have all diffrent life stages, and thats my guess without a pic. Usually they look like stars and have little balls on the end of their arms, and are VERY tiny. HTH

Thanks for all the positive feedback and IM's guys!!

hey helfrics chick thats my photo i posted on rc in the frag haha :0 glad i could help,

^ Huh? What pic?

awesome work HC!

you used my diatom pic

just found one of these buggers in my colony!

got him out looked kinda cute.
came to check out this thread!
BINGO!
die scum die!

This kinda looks like a nudi. The polyps close when it is around. I tried to syringe it off but it would let go! any help?

any thoughts? I am leaving tonight and would like to identify and destroy (if applicable).

Great thread. Lot's of great info

I think i have Asteriniid stars. they look like Campbells Chiken and Stars soup and they have taken over my tank. I hope they are the harmless kind, but since they have taken over my tank, how do i get rid of them?

Here is a pic attached

unlimited food supply for Harlequin shrimps!

The harmful critter section scared me, literally. I fear for my tank now..

I also fear for my mantis tank, because I have reason to believe that there is a MANTIS in it...

But every thing was very helpful, except now Im scared.

Nanu Nanu: Def a zoa nudi... hate to tell you this hun but you should take out all of your Zoas and give them a FW and Lugols dip. Where there is one nudi there are more.

Doapamine: Yea definatly a softie nudi. Most come in on finger leathers from what I have encountered. Check the underside of all leathers and especially at night. They can do some real damage... dont forget to look for eggs too.

Vic:

Plankton: Only good way is to remove them manually. Find someone with some harlequin shrimp, they eat them right up!

Click to view attachment
Blue Tailed Syllid Worm.

Never did get an official name for this guy so I made one up...

Very good job-- Sticky!

Edit: Cool, it already is!! Good Job Again

Thank you for this Incredible list, I have searched everywhere for the fan worms that I didnt know were fan worms until this post and now Im like 'whew' so first a thank you to you... Now my question to you is do the fan worms also come in a blackish gray color? (Not very pretty, but thats ok if it is harmless) the 'fan' is kind of crown shaped? I mean it isnt flat like a fan but more like in a circle? I kept calling it a tiny feather duster like thing but the internet did not comprehend, lol. So that is my little mystery critter, blackish gray feather-y crown, about a quarter to a half inch long that sucks back in when you get near him. Thank you! Tanya

Great thread! Thanks for posting.

WOw this is def the ultimate id thread.. Love it. But, the sundial snail? I never knew he was harmful! I have one living in one of my nanos.. Hope he didnt lay any eggs. I guess he gots to go now!!

thank you sooooooooo much for this thread!!!! i've been yanking out good things...

Awesome all!!! I added a collonista snails .... they look similar to sundials yet very tiny. Glad this is so informative for you all!

would this be Collonista?

Thanks for all the hard work HC. I was trying to figure out what kind of snail hitchhiked onto my colony of zoas. According to your pictures, it looks like a Stomatella snail.

can someone post the link for the website that has a large amount of hermits on it?
its foriegn

How big are Spaghetti worms? The picture looks like it is standing up. Do they always do that? the other day I woke up and went to stare at my live rock (that is all I have so far...it has been in there for 9 days) and I saw all of these little tube like trails in my sand and over some lower parts of the rock. I figured it was some kind of worm. Well just now I saw something. At the end of one of the sand tube/trail things I saw what looked like spider webs waving in the water. They are very fine and white. When I got a better angle I was able to see through the sand tube/path thing (my sand it white). The end looked like it had something in it that was a brownish orangey color. And the spidery web things seemed to be coming from it. Then I saw one little weby thing grab a little black speck off the sand and move is closer to the.... mouth I guess. But it is all so little it is hard to tell. The sand tube/path it seems to be leaving is only about 1 - 1.5 mm wide. Could this be a spaghetti worm? If so should I try to get rid of it? I almost grabbed the turkey baster right away to try to suck it out. I figured I might not ever be able to find it again. But I couldn't bring myself to do it with out knowing what it was. It would have been creepy if it was bigger. Some the the webby/tentacle-type things were reaching out about an inch and half! At first I though there were two until I saw that they all brought the gunk they grabbed back to the same place.

Any advice will be great. As you can see I am very new at all of this. Other then an Amphipod this is the first life I have seen other then the algae that seem to grow each time I leave the room for 5 minutes!

http://www.recif.be/article/hermit.htm

Very happy you added those, saved me a forum thread! Took a flashlight to my rocks after I turned off the light on the first night and found about ten of those little guys in an area that couldn't have been more than 5 square inches. All of them were barely bigger than pinheads. I did think they were sundials at first, and was worried I'd be stuck plucking them off with tweezers for years. I turned on the tank light to get a pic since my camera won't do dark shots, and all but one were gone when I got back to the tank.

I'm pretty sure the white worm-looking things are the remains of various calcareus(sp?) worms. They're hollow tubes that are about bone-white. Some are long while others are very short. Is that what I am looking at as far as those go?

Awesome job HC ...

I did not seem to find a description of a type of rock worm that will create holes in LR or eat the stony part of your frogspawn. I have spotted a worm in the rock that is like purple/blue color. Not sure what that is ... any ideas?

I was frightened to find something new in my tank today that was indestructible. Luckily I found this thread and have since declared him a chiton! I had never heard of these guys before and there are others here that are new to me.


Thanks for your time this works great!

What do you think this is? It does not seem like flatworm because it does not move like a slug. It is only 2-3 mm long and it runs kinda fast and looks like it can swim in the water too. Is this the Cirolanid isopod or some other kind of isopod? I found these on a set of ricordea I just bought. They were hiding at the back side of the rock.

Identified by Diane as "A specific kind of sphaeromatid commonly called a "sand skater." Reef safe."

Sail?
(it's on the front glass)

can you post a bigger size pic please? does not look like a snail.