My Live Rock has Crabs!!! (a few newbie Q's i need some advice on)

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stu

Aquarium Advice Apprentice
Joined
Aug 6, 2008
Messages
44
Location
Australia
LOL...i got my live rock yesterday and put it in my tank and today when i got home and turned the lights in my tank on i saw a little clear looking crab crawling across the rocks!!! aHave to say i was pretty excited when i saw him in there...lol. It's the little things i tell ya :wink: There are a few other little wormy looking things (with legs) i've noticed on there as well. I have a few questions i'd like to ask if anyone can help me i'd appreciate. I've been reading lots and lots and i still have a few queries. Here goes....

My tank at the moment has only coral sand (4.5 inches) and about 4kg of live rock (half what i will be putting in there, need some more funds to get more....expensive) I'll most likely be going for some small saltwater fish...probably 6-7 in total. Or i may end up going a few small corals and 3-4 fish...haven't decided 100% yet and will buy my lighting etc if i decide to go the coral route.

1. I have a filter in my tank that basically sucks water up into the lid, drops it into some cotton media and then the water runs back into the tank. What media should i get to mput in with my cotton filter media for the bacteria to live in. There is plenty of room for me to put something in between the tubing that drops the water onto the cotton media...so i'd like to put something in there, it will have plenty of oxygen there as well as the water freefalls about 1" onto the media. Have space for 2 different things if i want. My LFS said to put some carbon media in there, but i don't trust them. What media should i put in whilst (fishles with a shrimp) cycling and then after the cycle when i add fish. I'm thinking of getting some of those ceramic ball like thingies and something else? I know i should use a canister or some other type of filter but i'm going to do it very slow and see how i go with my jebo and it's "in lid" filter. I'm in no hurry with this project.

2. Is it ok to do my cycle with only half the live rock, and will adding the rest of the live rock screw up my cycled tank? I need to know this as i need to work out if i should buy more live rock ASAP or if it's ok to wait a few more weeks to get it. (this is totally based on my funds at the moment, but if i must get it in their ASAP i'll get it ASAP)

3. Will the cycle kill my little crab and the other life on my liverock :sad:

4. I added my shrimp about 20 hours ago and today i came home and the water had gone really really cloudy, i've read from other threads this is what happens and it's a bacteria bloom...my question is, should it become so cloudy do fast? I think may have used to much shrimp (prawn :)). I can't test the water at the moment as i only have a tropical test kit, my saltwater kit is in the mail. Just curious that's all, i put a really big prawn in the stocking..and my tank is only 120 litres. Oh yeah, i have to add that when i come home today my house smelt like a rotten fish....lol, that prawn stinks so bad, so i put the lid back on my tank for now and it's keeping it contained for now.

Thanks for any advice on the above. The main thing is the filter media. I've tried reading about lots of filter media but so many places say different things about different media and it's really confusing for a newbie like me.
 
Last edited by a moderator:
I thought I'd add a few pics of my setup.

My tank as it currently is, i plan on getting my live rock wall about double the height i have now. There is a lot of tiny bubbles in the tank, however this is caused by the pump that blows bubbles into the tank near the top of the pump, because the water is a little low it seems to make alot of bubbles, when i top it off with water it settles down to about half. (i'll top off the water after i add the rest of the live rock)

tank1.jpg

The section of my filter i have for some extra media (it's actually alot bigger than it looks in the pic 9" x 5.5"). There are 2 compartments as well.

tank2.jpg
 
First off welcome to the site. lets see if I can take a stab at some of your questions

1. During the cycle I would not keep any media you don't want to absorb anything that helps feed the cycle along. Afterwards Carbon is good or some people use Purigen because it is rechargable and last a bit longer. And Kudos for doing the fishless cycle looks like you have done some research.

2. It is fine to do your cycle with half of your live rock however if you add more live rock later you will have to cycle it in a seperate container before it is place into your main display. My prefferred method is to buy all of the live rock at once uncured and then cure it in the main display this jumpstarts the cycle and cures all of the rock at once.

3. Its hard to say what will live from an ammonia nitrite nitrate spike but you would also be surpised how tough those little crabs are. I had a hermit crab that lived threw the cylce and my tank crashing he was the only living soul.

4. It doesn't sound like you have anything to worry about but testing your paramater is crucial during the cycle any time you have an issue with your tank and post on the site the first question you are asked is did you check your paramaters and what are the results.


Just to add if you get enough live rock (USA about 1.5-2pounds per gallon) and have lots of flow via powerheads you dont really need the mechanical filter other than a place to store media. Hydor koralia's seem to be the favorite powerhead among saltwater aquarists.
 
Just to add on.
1. You can add LR rubble in your compartments as opposed to the ceramic rings. Just make sure they are always submerged in the water. Carbon is only good for about 1-2 weeks depending on your bioload/feeding habits. Personally, I run Purigen in one of my compartments.

2. You can always add more rock later. I prefer to use about 75% base rock (dead white rock) and 25% LR (as it will seed the BR). The BR is a lot cheaper. You can add cured LR (rock that has the beneficial bacteria on/in it) without having to re-cure it (assuming your LFS is not too fat away) and it stays moist from the trip home. You can also add more BR at a later date, just make sure there are no dead critters in it, otherwise you can possibly see another mini cycle as the dead critters decompose.

3. Figi is correct and after a few months you will see all kinds of new life crop up.

4. The cloudiness is not a diatom bloom, but just the decomposition of the prawn. PS; I edited your post, we like to keep it family friendly....

I also agree, props on the fishless cycle!
 
Stu,

You will come to find all sorts of "hitchikers" on liverock that you bring home (or order online if thats your preffered method). Personally, most of my critters came on live rock. One rock alone produced a Sally Lightfoot crab, 3 Emerald Crabs, 1 Black Brittle Starfish, two snails and an unidentified crab which reminds me...I need to post that.

Anyways, always expect critters coming out of the liverock.
 
I'll most likely be going for some small saltwater fish...probably 6-7 in total. Or i may end up going a few small corals and 3-4 fish...haven't decided 100% yet and will buy my lighting etc if i decide to go the coral route.

I agree with what everyone else has said. No need to add to it at this point.

The above statement concerns me a bit. I would say 3-4 fish would be pushing it for your tank. 6-7 is way too many for that size tank.
 
Hi guys, thanks heaps to everyone for the responses.

@Ziggy, i here what you are saying...my tank will be a very slow process, i will add 1 small fish at a time most likely and watch my water levels to see how well my tank copes with the bio load. I have plans to upgrade my tank to a larger tank in the future providing i can keep at least a small amount of marines for now. I really have no hurry for this tank, just easy does it and watch how the tank (and water) responds.


@Roka (sorry about the required edit, will watch what i say)


Otherwise i'm happy with my setup. I have to say that after 3 days of having this setup, i'm being totally amused by the live rock alone. Today i started to leave the lights on all day and when i came home today i noticed some kind of worm sticking out of one of my rocks and he qent back in really quickly after i put the torch on him. There is also some small flower looking plants? That open themselves up when the lights are turned on and they close themselves into a small bubble when turned off.

I went and grabbed a few more pieces of live rock today.......got one of the small pieces out of the bag and got the fright of my life when i turned it over and there was this THING crawling all over it, i'm not sure if this is a starfish crawly or if it's just a really really long bug or multiple ones?......I took a pic of it to show you guys, also 1 other thing...I have this cocoon looking egg? growing on the side of one of my rocks that has something yellow and black inside of it? Any ideas what it might be? It's about 1cm big now and seems to be growing rapidly. And also is my creepy crawly i got today something i should be wary of not touching as he might sting me? I don't think i've ever been as amused with something as i am by this rock....i don't know if that's sad or not but i'm enjoying it :)

Any identification of these items in the pics would be greatly appreciated...because right now i'm a little wary of the crawly i got today....Will these things be ok in my tank?

umm.jpg

umm1.jpg
 
Just another thing that might help identify the crawly in the first picture, this thing is huge....i moved the piece of rock that he has himself totally threaded through and his arms/legs? started to extend and i would say at the very least he would stretch about 20cm....and i've been able to count at least 3 arms/legs....so i'm not sure if this thing is a starfish like creature or if there is actually two of them...he literally has himself woven right through that piece of rock, in one side and out the other, and then out some other holes as well.

I've tried searching, but is there any resource out there for identifying different species that aren't fish?

UPDATE: I think that he might be a brittle star fish of some species? Still not sure about the cocoon thingy though. Can't wait to see what might come out of it :)
 
Thanks for the info mate, when i woke up this morning and turned the lights on i got a good look at him as he was out cruising around. He's a 4.2 legged star fish :) One of his legs has been cut almost completely off. Looks like an old injury though as it seems to be healed over.

Not sure we're going to see what the other thing is.....i think mr starfish might have tried to snack on it overnight :(
 
I agree with chisel on the first one. The second pic looks like some type of sponge. A good filter feeder.
 
Ok,thanks again for all the replies :)

Little update, i think my star fish is in the process dieing.....When i came home today i found him missing one of his legs so he was then a 3 legged star, now tonight i've come home again and he's missing another one of his legs and he doesn't seem to happy. Not sure how he's losing his legs, however the legs he's lost are still moving??

I have another picture for ID :) This fellow was out playing with the dropped off leg from the starfish when i turned on the lights tonight (then he went straight back to the rock when i turned the lights on)

Ignore the starfish leg at the back, just the gritter looking thing in front.

crawley2.jpg
 
It appears to be some type of polychaete but I'm not certain what type. I can't see the podia (hairs) very well if there are any... it may be a fire worm. I know how hard it is to photograph these things but really, a more detailed picture would help. It may or may not be preditory, and to me doesn't look like the common bristleworm we normally see. I'd keep an eye on it or, when in doubt take it out and move it to a sump or fuge area if you have one. Sometimes it's better to err on the side of caution with unknown worms.
 
Hmm...if i see him come back out i'll grab him out for now. Your right they are hard to get a picture of, i took about 30 of it and only about 2 are anything veiwable. Here's another one i got, not resized at all so a little larger.

He didn't really have hairs on his body, however he had some feelers at one end. This is the best pic i can get for you until he comes back out. You can see the feelers/antenae on one end.

crawley2-1.jpg
 
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