Help with some hitchhiker questions

[Dewey115]

I have found a few different things in my tank and have spent about the last month trying to ID them or judge what they are. I will try to get some pics of the bristle, but the other things are nearly impossible to photograph. Firstly on top of the water in the tank are these little things that move very quickly. They move like the little water striders on ponds or creeks but are very small (maybe half the size of a pencil eraser) and they move very very quickly. I cant tell if this is something I got from LR, maybe from acclimating livestock and they transfered over to my tank, or even something more local that just decided my tank was a nice place to live. I dont even know where to start looking for what they could be, so any ideas on where to start would be very appreciated.

Secondly there is a type of bristle that is different from the main ones in my tank (which I have IDed and are safe). These ones are more flat instead of round (so have kind of a distinct top and bottom). Around the sides of them there are white bristles with some red bristles as well. They are mainly just plain pink in color, however the middle of them is a darkish color almost a purple color, but to me looks more like coloration of the internals just showing through the pink. I have noticed that two of them are quite large (got them from LR I got recently, so these are much bigger than the otherwise small bristles I have now). The dark coloration seems to be more pronounced after they eat something (and I have strong feelings that these guys have contributed at least in part to some deaths in the tank). For mental image sake, think of the dark part as a purple stomach showing through, this may be the case or may not but for discription purposes it works.

Lastly there is a small cone shaped thing that has been moving around on a piece of the LR. It is shaped like a barnacle but without the top open. It is light yellowish colored and has black stripes radiating out from the center. It was about the size of the tip of a pencil (break off the lead part of a sharpened pencil and thats what this looked like) but has since grown a little bit. It moves about an inch per hour. Again any ideas where to get started would help alot. I dont even know where to begin to try and ID this thing.

Thanks for any thoughts or ideas.

Rick

[mogurnda]

No idea on the first thing. The second things sound like Pacific fireworms, Eurythoe. They are generally considered harmless unless very big, but there is always the possibility that they are causing trouble. What has been dying?http://www.reefs.org/hhfaq/img/faq_bristle.jpg

The last thing may be a limpet. Small molluscs with conical shells. They spend most of their time grazing, but will include sponges, tunicates, and sometimes soft corals in their diets.

[Dewey115]

Thank you very much, both were just as you said. A quick search and I had alot of pictures of both so thank you :-) As for the deaths I had a peppermint shrimp that was killed quickly by something. I was watching when it happened, but the direct view was behind a rock so I wasn't really paying much attention. He went around the rock and within 3 seconds was twitching and kicking half swimming away quickly dying (which by the way my nassarius snails loved). He had a small section of his skeleton lifted off the top of his head which definately had not been a part of say his molt (was much thinker than his molt). The only other thing in the tank is a Goby/Pistol Shrimp pair but both were on the other side of the tank when it happened so it wasnt either of them. Later a Sally Lightfoot Crab (the incorrect name for them, it wasn't a true sally lightfoot) but this crab died after about a week of being what appeared to be kind of relaxed and active. He moved around eating most of the day, but really hiding or acting scared. Then one day I came home and he laying half upside down dead. I haven't really seen anything to make me think there is a mantis or crab or anything hiding as a hitch hiker. There were two of these worms each about 8 inches or so that were in there. Had some clown fish about 2 months ago, but they didn't show any signs of being killed and we pretty much settled on them dying of illness(es). Any thoughts?

Rick

[mogurnda]

One of my least favorite type of questions is about mysterious deaths. I can never come up with much of a clue. Maybe a mantis? I have just found two in some new live rock, and only because I saw their little eyes peeking from the rocks. No clicks, even when they are fed.

[Dewey115]

Guess I will double check it to make sure, maybe randomly check the back of the tank to make sure, if nothing else it will allow me to rule it out if I dont find one...

Rick

[benjen]

Also, check for any "empty" shells that might contain a shell-breaking reef hermit. (I got one of these mixed in with my scarlet hermits.) There are more killer inverts than just mantises. However, a pistol shrimp could do the sort of damage described as well, I'd guess.

[Dewey115]

Well the Pistol shrimp is still very small. He picks on the Nassarius snails when they go into the entrance of their burrow, but even they are too big for him to do anything more than harass. Unless he is just playing with the snails I dont think he is big enough to do much other than be a pain. The "Sally Lightfoot" looks like it was killed on top of the highest of the LR in the tank, I have yet to see the Pistol really climb (can they?), or even do anything at all more than a few inches from their burrow. I have checked all of the shells in the tank and all of the empty ones look empty (I took them out just to be sure) and all the snails/hermits are just as they should be. Thanks for the suggestions, the more you guys offer as ideas the more I can eliminate and the better I feel. The worst part of all of this is having no clue what happened. I think I am going to take out the bigger bristles, even if they have nothing to do with it or if it was a freak one time thing, there are enough small ones in there I am not worried about losing the big ones. Better safe than sorry. I am still checking for any hitch hiker I may have missed, but I haven't seen any signs of anything so far. But I have only really been looking for a day, still cant rule it out :-( Thanks for the help guys, I really appreciate it

Rick

[mogurnda]

I have discovered most of the hitchhikers, good and bad, at night or in the early morning before the lights come on. It's amazing what can be in there that you know nothing about.

[cpn_aaron]

yeah, hitchhikers can be everywhere. I have a goby who refuses to feed or show himself if I'ma round and yet he's lived and grown with me for 6 months now. He lives on copeopods in my lr I suppose.

Mantis can be a pain, but so can pistol shrimp. If some people recall I had a pair about 3 months ago who lived ina small tank with a yung southern puffer and some FL species gobies. The female ate the male and then killed and ate most fish within two nights. I sent him back to the grass bed where he came from. Lots of people like pistol shrimp, but I don't trust them.

If you don't hear a lot from your aquarium, things like stone crabs could be the culprit. For about 5 months I had a 30 gal that seemed to breed stone crabs just to kill off my fish. The fish would disappear and I'd find a crab much larger maybe weeks later. I upgraded to a 75 gal I bought from a guy who was getting out of the hobby and realized why he had so many fish deaths. He introduced more crabs into my aquaria.

So the best way to tell if you have a crab or mantis problem is trap them. I use one of those cheap gladlock storage containers and cut a cross in the middle of the top to allow access. I place some of my frozen silversides I feed my other fish in the container and leave it over night. I've caught plenty of potential threats to my tank and got my freshwater oddballs a tasty treat of crab. This might attract those worms too if you're looking to remove them from your tank as well. It does catch a lot of your snails since they follow the smell.