Green Porcelain Crabs at surface of water and climbing out!

[SauceyReef]

I got a 6 green porcelain crabs from ReefCleaners. 2 went into the Evo, 1 went into the six gallon orb, and the other 3 went into the six gallon Mangrove tank. The 3 in the Mangrove tank have been climbing up near the surface of the water since adding them a few days ago. 2 of them are on the mangrove stalk literally as far up as possible hugging the surface. This morning I found the 3rd literally out of the water on the side of the glass. If I poke them they react, but dont really leave the area. I do see them fanning sometimes.

Is this normal for them? A sign something is really wrong with the tank/water? I have corals, hermit crabs, the mangrove, other life in there no problem. The other three in my other tanks dont seem to be doing this. In fact I have never heard of them doing this.

 

[SauceyReef]

Came home and they’re all still in the same place.

 

[yanetterer]

My first thought is low oxygen levels, but it looks like you have good aeration.

When I tried multiple porcelains (the white ones) in a 30 gallon breeder they quickly killed each other until one was left. I haven’t read anything about them being aggressively territorial, but have you seen any aggression towards each other?

Have you tested any water parameters?

 

[SauceyReef]

My first thought is low oxygen levels, but it looks like you have good aeration.

When I tried multiple porcelains (the white ones) in a 30 gallon breeder they quickly killed each other until one was left. I haven’t read anything about them being aggressively territorial, but have you seen any aggression towards each other?

Have you tested any water parameters?

Salinity: 1.026
Temp: 76

Agreed - it cant be the aeration as I have the bubbler air tube, and a Hygger Mini in there. Plus shouldnt the Mangrove be reelasing oxygen as well? (not sure if roots do that). I just added these 3 porcelains a week ago and they went through horrible shipping delay of 6 days. I had bought six of them. 3 went into the Mangrove Vase, 2 in the Evo, and 1 in the Reef Vase. None of the other ones are doing this and are hiding in the rocks. I contacted reefcleaners - they said they could just be looking for the most flow. The spot would make sense, but still the behaviour is super odd. The two on the mangrove stalk are right by each other. And again I found one out of the water yesterday on the side of the glass..

The tank struggles to keep any corals alive. I always assumed this is the Mangrove just sucking the life/nutrients out of the tank. The vase next to it is beautiful, and runs the exact same.

My tests on the tank are limited because I dont have any important corals in there, and it is more so to keep the Mangrove alive and happy which is never a problem.

Salinity: 1.026
Temp: 75
Nitrate: 0
Phosphate: 0
Age: 2.5-3 years

 

[SauceyReef]

1. 13.5g Fluval Evo
2. 6g reef bowl
3. 6g mangrove vase

 

[SauceyReef]

Like look at this…This can’t be normal!

I’m tempted and occasionally try to grab them to plop them in the other tanks, but they scurry down when I do.

 

[Roja]

Hi, pretty late to the thread, but in case the situ is ongoing, I'd like to add my own experience. I got a pair of local, wild-caught red/white porcelain anemone crabs about a month ago (didn't know they come in green - have to keep on the lookout). I have1 sand nem and 2 decent sized green BTAs, and it was sort of a temporary housing (around 5 litre AIO pico) for the animals before settling them into a dedicated shallow tank. All was well for a couple days, the crabs took to different nems and there was no aggression whatsoever. One might before lights out, I saw one of the crabs hiding behind a nem - I thought it was about to molt. Then I saw it shooting backwards across the tank, much like a disturbed shrimp, beating it's little squat tail, and this took place a few more times and the crab started to drop several of its legs. Fast forward a day and it's lost around 3 legs. I found it clinging to my thermometer, right at the waterline, and it won't budge no matter what I try. I even picked it up and dropped it on to the nem, but it shot back up and clung to the thermometer without letting letting go. This happened a few times and I realized everytime I drop the crab into the tank, the other crab rushes out with its big claws and tries to gapple with it. This makes the crab drop its legs and shot back into a 'safe zone', where the other crab can't get it - hence the thermometer. When I realized this, I picked the crab up and kept it in the overflow chamber for the time being - as I didn't have any other place for it to go (my other tank has a group of camel shrimp). It was visible stressed and didn't eat for a while, but then got better. I was waiting for the limbs to regenerate so I can set up a new tank for it and put it there. One day there was a problem with my water level and the overflow compartment ran dry while I was at work - the crab didn't make it and was above water by the time I came home. I was devastated. When I went to remove the guy, I realized it was holding eggs. It was horrible but there's nothing to be done. Today I noticed that the offending crab currently in my pico is also nursing a brood of eggs. It seems that you can't mix porcelain crabs of the same sex - have either a single one or a definite pair. The crabs get aggressive and territorial with their same sex.

This makes sense to me cos since your mangrove tank is the only one with 3 crabs, it's likely that they might be all male or all female, definitely two of them would be the same sex. I think your crabs are trying to get to a safe, unreachable spot - hence anything closer to the water surface. I suggest you immediately separate the little guys before the ordeal goes south. This hanging-at-the-surface behavior is exactly what I observed when I saw the female-female aggression.

If the other inverts and your corals are doing fine, I would rule out a water-chemistry issue.

Sorry bout the rant. This is my first reply to a thread, apart from introducing myself a while ago and I wanted to be of some help. Hope I'm not too late and this helps you and the crabs out!

 

[SauceyReef]

Hi, pretty late to the thread, but in case the situ is ongoing, I'd like to add my own experience. I got a pair of local, wild-caught red/white porcelain anemone crabs about a month ago (didn't know they come in green - have to keep on the lookout). I have1 sand nem and 2 decent sized green BTAs, and it was sort of a temporary housing (around 5 litre AIO pico) for the animals before settling them into a dedicated shallow tank. All was well for a couple days, the crabs took to different nems and there was no aggression whatsoever. One might before lights out, I saw one of the crabs hiding behind a nem - I thought it was about to molt. Then I saw it shooting backwards across the tank, much like a disturbed shrimp, beating it's little squat tail, and this took place a few more times and the crab started to drop several of its legs. Fast forward a day and it's lost around 3 legs. I found it clinging to my thermometer, right at the waterline, and it won't budge no matter what I try. I even picked it up and dropped it on to the nem, but it shot back up and clung to the thermometer without letting letting go. This happened a few times and I realized everytime I drop the crab into the tank, the other crab rushes out with its big claws and tries to gapple with it. This makes the crab drop its legs and shot back into a 'safe zone', where the other crab can't get it - hence the thermometer. When I realized this, I picked the crab up and kept it in the overflow chamber for the time being - as I didn't have any other place for it to go (my other tank has a group of camel shrimp). It was visible stressed and didn't eat for a while, but then got better. I was waiting for the limbs to regenerate so I can set up a new tank for it and put it there. One day there was a problem with my water level and the overflow compartment ran dry while I was at work - the crab didn't make it and was above water by the time I came home. I was devastated. When I went to remove the guy, I realized it was holding eggs. It was horrible but there's nothing to be done. Today I noticed that the offending crab currently in my pico is also nursing a brood of eggs. It seems that you can't mix porcelain crabs of the same sex - have either a single one or a definite pair. The crabs get aggressive and territorial with their same sex.

This makes sense to me cos since your mangrove tank is the only one with 3 crabs, it's likely that they might be all male or all female, definitely two of them would be the same sex. I think your crabs are trying to get to a safe, unreachable spot - hence anything closer to the water surface. I suggest you immediately separate the little guys before the ordeal goes south. This hanging-at-the-surface behavior is exactly what I observed when I saw the female-female aggression.

If the other inverts and your corals are doing fine, I would rule out a water-chemistry issue.

Sorry bout the rant. This is my first reply to a thread, apart from introducing myself a while ago and I wanted to be of some help. Hope I'm not too late and this helps you and the crabs out!

No problem - I appreciate the replies. The only thing that makes me feel really comfortable putting a bunch of these in a small system is the fact in the wild they have found thousands of them in a single cubic foot. They are invasive in a lot of areas. If they can concentrate that much in the wild they must be fine with 10-20 in a small tank. Maybe during mating they can just be brutal to each other. At $5 a crab, and the fact they are overpopulating a lot of the reefs makes me feel comfortable if I get some losses.

I took all of the crabs out of the Mangrove tank though but one. Even though others were telling me it was fine - I did not trust them all hanging at the top and climbing out of the water. The other ones I put in the other tanks like to hang out near the top, but not at the surface, and dont climb out. I feel like I made the right decision.

I have a feeling this Mangrove is sucking out all the Magnesium or some other essential element in this tank. Keeping anything alive is difficult long term.