Emerald crab question

[Psiber_Syn]

Ok had these emerald crabs for some time never really eat bubble algae like they are supposed to but I have witnessed them eating polyps off of my birdsnest/stylo colonies is this normal has anyone else experienced this it upsets me and I'm thinking of banishing them to the sump they all including the red leg hermits stay in the bnest/stylo they eat it till there is no polyps left in places just white skeleton could this be from reef chilling the nests? Or do they eat them in the wild?

 

[melypr1985]

I haven't had any issues with my emeralds or hermits eating my birdsnest. Not all emerald's eat bubble algae. The only time I've seen hermits eating a coral it's because it was already dying and they were eating the dead tissue. Maybe your birdsnest isn't doing so hot and they are just cleaning up the mess before you see it? We can call in the [HASHTAG]#reefsquad[/HASHTAG] for more opinions.

 

[bobman]

Do you spot feed the birdsnest? If so they could be going after the food and a side effect is the coral will get nipped.

 

[Psiber_Syn]

I use reef chili just kind of pour what's left in the cup over the nest colony gonna stop doing this though lol that is what I thought also

Got a bunch different ones all clumped together and you can see spots on a lot of them where it's just bare white and I observed one eating the pink nest when I posted this almost 1/3 was all gone I ran the emerald off and in minutes was back at the same spot eating again everything was perfect yesterday with it and this morning but for home from work to a buffet going on months ago I had a big sour Apple colony and they stayed up in it all the time until one day total rtn over night now thinking they may have been eaten :-(

I read somewhere only the female emerald eat bubble algae not sure if it's true or not all mine must be makes if it is lol

 

[Shep]

Emeralds are one of those crabs that can be a real shot in the dark. Sometimes they are great and other times they can be a pain. I am pretty sure they have been know to pick at corals from time to time

 

[Psiber_Syn]

So got a good recipe for crab cakes lol

 

[Psiber_Syn]

He ate the whole thing and moving on to the next one see his claw up in the middle stupid crab

 

[Triggreef]

IMO and IME thats not from the emerald crabs. Mine hang out all the time in the stylos and birdsnest and cause zero damage even as they grab at the polyps. Next day polyps out just fine. You should look more at your parameters. Thats major damage and looks like mostly even skin tissue has recessed. The worst my emeralds have ever done is squish the tips a little here and there which is not a bad thing. It actually promotes new growth. And I have many many more emeralds than pretty much anyone.

I had about 60 in my 200g at one time and they destroyed every type of algae, bubble algae included. higher numbers are needed than you think to get these guys to do their job, but they will.

 

[Psiber_Syn]

I appreciate your experience I had this happen months ago with a huge colony which is what all the stylos and nests are sitting in it over night just rtn but the same emerald and red legs stayed in there

All Params are in range cal a little low but everything else is fine it's odd that just that one recessed
I watched him pulling at it yesterday and today it looks like this what params would affect the colonies the most?

 

[Triggreef]

It looks like several different kinds? Looks like the green one in front has some areas on bottom than have been dead and are now discolored. Looks like the pink nest in the back also has some of that as well as some fresh bright white death. And it looks like the crab is at the area of the nest that is currently shedding skin, so yes it will be pulling the skin off as its dying.

I've had some nests die at the same time others are fine. Have you moved them at all? I lost a big colony that I moved from the bottom to the top and within a week it perished. I've had mini colonies of some nest that just fell and I put them back and the same thing gone within a week. It's part of the game which is one reason to keep multiple frags of what you like.

I don't really see growth tips on those which IMO means they aren't growing (thriving) just sustaining.

Maybe nitrates/phosphates? I have some ora nests doing quite well in a tank with po4 regularly above above .24 ish so if your not that high, then look elsewhere. No3 though I keep low (<5) because thats easier to control.

 

[Triggreef]

So here is how your tips should look if that nest is happy.

 

[Psiber_Syn]

Would not enough light cause this? I just finished testing everything again

Alk 10 dkh
Cal 330
Mag 1400
Nitrate barely orange on api
Phos barely reacts
No ammonia or nitrites
Ph is 8.2 - 8.4
Temp 77

 

[Psiber_Syn]

Yes it's a few different kinds all together two green birdsnest 1 does have some issue on the tip the one that is totally gone was a pink birdsnest there are a few different green ones in there over time the bottom of some of them died but the tops have been great I have had them for at least 3-4 months is that long enough for them to start during if not flourishing?

 

[Triggreef]

Your Ca is way out of whack for how high your DKH is. That would cause this over time for sure.

I keep my DKH at ~8. Natural sea water is only ~7 and NSW Ca I think is around 420. So I mean if you keep it proportionate, at 10 DKH your Ca should be at around 500 to 520 (Guestimate I didn't do the math).

Here is a great article that might help. Although old its easily understandable. http://reefkeeping.com/issues/2004-05/rhf/

 

[Psiber_Syn]

I have read that article 100 times rhf is a smart guy


My alk takes a long time to drop the cal not so much we have been waiting out alk to get lower had been as high as 14 dkh Cal normal staus about 420-440 we are trying to set up two part dosing but waiting till alk drops a little more

Any advice on setting up the two part should we just start it now and see how it changes over say a week or wait till alk drops more?

 

[Psiber_Syn]

Also just done a water change less than week ago

 

[Triggreef]

Could add some Ca carbonate to get Ca up but from what I just read browsing through my own link, is as long as your above 360 your good.

My thought is if Ca is low, some other minor elements could also be low. I'd do some good size water changes to get things back on track, and once there then begin 2 part like you said.

 

[Triggreef]

Also I'd snip the tips of those nests about a 1/2 inch above any death spots and re glue, then trash all the dying pieces. Some people believe the bacteria thats eating that tissue will keep going. I'm on the fence about it. I've left some and had the corals recover. I've also had death go slowly through my tank from one piece to the next over several months all while maintaining very stable parameters.

 

[Psiber_Syn]

I have been battling the cal and alk and ph levels since the beginning never really getting them right cal normally stays in the 400 range alk has been the problem which has caused ph to never stay stable imo I just done 30% WC a week ago should I do another? This has been very frustrating it's like when things start to look good boom problems all over like now all my shroom have jumped off the rocks ones that have been on the same rock same spot for a year now they just float around getting frustrted

 

[Triggreef]

yeah if your maintaining by water changes only then its got to be pretty frequent changes. I might try a ca supplement in the meantime just be careful how much you raise it. Too quickly won't help things. Stick to directions on the specific supplement.

Best advice look into dosing the triton elements, or similar line from aqua forest. Can't beat the simplicity.