unidentified creatures in my tank

[psumba]

Hello everyone - been awhile since I have come to the board, so I have a couple of questions....
I have 2 unidentified creatures in my tank - wanting to know if anyone has any idea what they might be:
1) its a small brown crab, has light brown stripes with the darker brown body. Looks kind of "fuzzy". Thin pinchers.
2) Now this is the weird one. I have no idea where this guy came from.
It looks like it has a snail consistency body. 4 eye stalks, kind of the same mouth as a snail. It can stretch its neck and then it almost looks like its head looks like a horses'. Its body is pretty flat overall, has little bumps on it. The front of its body is green, back of its body is purple. I almost didnt see him the first time, he really blends with the coralline algae on the rock.
He was on the front glass the other day and his belly looks kind of psychedlic with little dashes all over the bottom and it looks pretty opaque.
Thanks for any ideas you might have.

 

[sistrmary]

The first one, I'd have to see a picture of because most crabs look about like that
The second one however, sounds like a nudibranch to me. (Congratulations, they're cool little things) It came out of your rock I'm not sure what kind, or what it eats, hopefully something that exsists well on your rock.

 

[psumba]

I figured that about the crab, but I am hoping someone can nail it from that description. I have never seen a dark brown one before.
Almost the same from as an emerald really. Cant remember if I have been able to get a clear pic of him yet. I'll post as soon as I have it.
As for the nudibranch, that was one of my initial guesses. I looked up some pics of one, and it didnt really look the same though. Arent nudibranchs more worm bodied? THis is pretty flat. And its not bright coloration.
If it is a nudibranch, will he be harmful to corals or anything else I should avoid?
right now he has ignored those I do have, and seems more interested in algae on the rocks and the front glass. He has just hung out with snails eating.
I do have pics of him, I'll try and get those up as well.
Any other ideas?

 

[jonthefb]

ok the crab, do his pincers come to a point or are they rounded and then flat, like a vise? if pointed, they are predatory, and i would reccomend gettign them out before they do some damage. if flat, they are herbiverous, and no need to worrk.
the slug thing. is there an observable shell? it quite possibly could be a nundibranch, but could also be like a turbellarian worm, whcih are usually flat, but have frilly edges, and are more laterally compressed than nudis.
pics would def. help
good luck
jon

 

[psumba]

ok I have finally been able to capture this guy on film....
This is my UFO
Can anyone tell me what it is?
I have had him now for months, he has grown, hasnt attacked corals that I have seen - only goes around eating algae.
I have found him in my filter a few times which is interesting,

 

[jonthefb]

looks kinda like a limpet, however it could also be an algae eatign flatworm or nudi, but lacks the external gills of a nudi. interestign

 

[psumba]

a limpet?
Whats that, that is new to me.
Do flatworms get big? This thing is like 3inches long. Very fluid body, he is laid out flat in the picture but when he streches his head looking around the thins up some.
At the bottom of the pic (dont know how well it comes out) are his eye stalks (qty 4). There are 2 at the very edge of his body, and then 2 more slightly up - snail like.

 

[psumba]

ok - I looked up limpet on the web.
They look close - but not quite. Limpets look to have a hard shell and a smaller foot.
This things whole base of the body that you see is one big foot.
This thing is sooooo odd.

 

[ags]

The first thing is a gorilla crab and will kill anything it can get its claws on. They are in the same family as the stone crab. They are prevalent in Gulf LR (aka Florida LR) and are a nuisance hitchiker. Most people who have purchased LR from TBsaltwater have experiences with them.