Something new in my tank

[2pac.biggie]

Hello people i just got home i found something walking across my tank :S i tryed taking a pic but it ran into my big live rock lol it luks like a small little crab or a spider lol its black and looks abit hairy. What can it be? And will it affact anythin in my tank?
At the moment iv got a hermit crab, clown sweet lips, parcular clownfish and a scooter bleny

 

[2pac.biggie]

Iv managed to tak a picture of the new thing i found in my tank please let me no if its a good thing or not lol

 

[oscarchic11]

it looks like a lil baby crab. prob hitchhiked in... idk if good or bad tho... im fw.

 

[2pac.biggie]

Iv had my tank now for 4months and i just saw it yesterday iv checked up on the net about this itl either be a emerald crab (which is a good thing) or a gorilla crab (which is a bad thing)

I need it to grow more to find out wat type of crab it is but i dont think it a hitch hiker coz i didnt have this crab b4 and if i did have it 4months ago i dont think itl be this small

 

[Pryzz]

Is it a reef or fowlr? Emerald crabs will eat algae until they can't find any then they will go for coral. They're opportunistic. So might be best to keep an eye on him.

 

[Schism]

Do the claws have black tips? A better more in focus pic will help ID.

 

[kdpuffer]

From the looks of it I would say it is not an emerald crab. They are green for starters and they have longer claws with small flat spots they use to pull algae. I would wager its not reef safe.

 

[2pac.biggie]

What is it then? And how am i meant to take it out cause its alwayz under the live rock and when it does come out it runs away once it see's me lol

 

[kdpuffer]

Place a glass in the tank propped on the rock near the crabs hideout and put some food in the bottom and it should trap the crab.