Crabzilla gone nuts!

[Tristan]

My emeral crab which I have had for over 2 years went berserk today. I
just happened to look at the tank and it was sidestepping along the
tanks glass with a claw full of zoo's and a yellow clown goby (JB who
is only about 1/2=5/8" long) in the other......Guess the crab wanted
some meat with its veggies. JB is the clown gobies name and it stands
for Jelly Bean as that is about as big as it was.

Anyway JB is history. In the over two years I have had this emerald
crab its been totally trouble free and has minded its own business.
Just picking algae etc and holding out in its caves and hollows. I
have not noticed any other missing fish or damages up until today
either. Its not like its not well fed as the tank gets two rolled up
pieces of nori algae on a stone in two different places for all the
veggie eaters every day.....One roll of Red and one roll of Green is
what I feed for variety.

So right now crabzilla is in a pico tank, a totally bare pico tank
with not even a sandy bottom to keep him company........Debating on if
I want to put it into the undesireable tank I am once again setting up
or just trade it in on a smaller emerald or something else. I guess
no crab can truly be trusted......


-------
I forgot more about ponds and koi than I'll ever know!

[Pszemol]

"Tristan" > wrote in message ...
> no crab can truly be trusted......

Just in his defense...

You did not see him hunting this fish donw, didn't you ?
It is quite possible the fish died for different reasons
and crab helped himself to fish corpses... right ?

p.s. I would be glad to rescue this emerald crab from you.
Where are you located ?

[Tristan]

Well in a way I seen enough to convince me of it. The little fellow
usually took refuge in the corner of the tank about 1" above the sand
substrate once the lights went out and lunar lights came on. I could
look in there at all hours and always see him in his corner.....bedded
down.....Right off that corner is where the zoo's were located as
well. I seen crabzilla in and around those zoos earlier, (bout 30
minures or so) and seen the fish as well, and there was certainly
nothing wrong with that fish up until lights out, and within 30
minutes of lights out crabzilla had it in its claw along with zoo's. I
seemto think he grabbed zoo's first, spotted the goby and went for it,
since it was so close. Most of those clown gobies are very very dumb
when it comes to allowing much larger fish or predators to get near
them. They are just too trusting of others.....As for me, say what ytu
want, but the crab took advantage of a situation and got that goby.
Its not the first reported account of a mithrax (emerald) crab
catching fish, thats for sure.

Emerald crabs are only about 6 to 8 bucks around here, and I do not
see how they could be that expensive anywhere else in the continental
US either. Drs foster and smith have them as well. I just have him
relocated for now until I decide what I am going to do with him. Like
I said, he had one thing going for him when I caught him, he was not
large enough to turn into a crab cake ;-) and I am not into flushing
unwated or problem critters........This emerald crab is quite large
and I have had him a long time 2+ years or so at least.

My statement still stands.NO CRAB can truly be trusted!



On Fri, 16 Feb 2007 13:46:29 -0600, "Pszemol" >
wrote:

<<>>"Tristan" > wrote in message ...
<<>>> no crab can truly be trusted......
<<>>
<<>>Just in his defense...
<<>>
<<>>You did not see him hunting this fish donw, didn't you ?
<<>>It is quite possible the fish died for different reasons
<<>>and crab helped himself to fish corpses... right ?
<<>>
<<>>p.s. I would be glad to rescue this emerald crab from you.
<<>>Where are you located ?



-------
I forgot more about ponds and koi than I'll ever know!

[Pszemol]

"Tristan" > wrote in message ...
> Well in a way I seen enough to convince me of it.

This does not seem to be a proof holding in the court ;-)
I am not convinced.

> As for me, say what ytu want, but the crab took advantage
> of a situation and got that goby.

These guys are not hunters. They do not have super good vision.
They are not fast enough to catch live fish, they cannot paralyse
them so fish could escape. They need to smell their food.
Live fish do not smell as dead one do... not as attractive.

> Its not the first reported account of a mithrax (emerald) crab
> catching fish, thats for sure.

Wait a minute.
You have not reported mithrax crab CATCHING fish here!
You only reported seeing it dragging a dead fish... right ?
And many other reports are similar: aquarist see crab
eating fish and they ASSUME fish was hunted down alive.

And of course fish cannot die on their own, it never happens, right ? ;-)

> My statement still stands.NO CRAB can truly be trusted!

Remember this: innocent until proven guilty! :-)))
Be fair and do not say this crab killed this fish, because
it is only your speculation - you did not see it happened.

[Gill Passman]

Well somewhere (or maybe not anymore) I have a mithrax crab in my Nano
tank....haven't seen it in eons.....but after I got persuaded to buy it
I went out and did some googling....and found that they do have a
reputation for picking off fish.....but my clowns are doing fine....and
the snail losses I put down to the hermits.....My point here is that it
is not always as clear cut as it might seem - sure the goby might have
died and the crab was picking up carrion....but OTH maybe it
didn't......It is a dog eat dog world in our tanks....and in
nature.....Personally, if I had any doubt I would either give it a new
home myself where it wouldn't do any damage or go and do the trade with
the LFS....

Gill

[Tristan]

Well your more than welcome to view it any way you want. I have seen
this crab setting on a hard tube coco worm and grabbing at the crown
as it would come out. It did the same to my feather dusters. It would
literally set there and grab at the crowns. Sometimes it hit the
target other times it missed...... Crabs are opportunistic feeders, as
they will grab a fish if they have half a chance, Lots of fish goes
into a sort of trance when they sleep. I used to be able to reach in
the tank and touch a chalk basslet I had when it was asleep, but if
awake you could not get within a foot of him. I see no reason to
believe that that crab did not slide up along that little goby while
it was in that corner and grab it. I have seen those yellow clown
gobies set on a coral and have another fish just come up and bite at
them.....they are overly trusting fish.

Of coarse fish die, but this crab was within an inch or two of the
fish and fish was alive and well for it to just arbitrarily drop over
dead right as the crab was there and in minutes time later it had that
fish. I still do not buy the crab did not do it. That crab grabbed
that fish, bad vision or not, dead fish smell or not, it seen an
opportunity in my eyes and took it. ;-))


-------
I forgot more about ponds and koi than I'll ever know!

[Pszemol]

"Tristan" > wrote in message ...
> I still do not buy the crab did not do it. That crab grabbed
> that fish, bad vision or not, dead fish smell or not, it seen an
> opportunity in my eyes and took it. ;-))

Judge:
"Have you witnessed defendant killing this fish or you have not ?" :-)))

[Pszemol]

"Gill Passman" > wrote in message ...
> Well somewhere (or maybe not anymore) I have a mithrax crab in my Nano
> tank....haven't seen it in eons.....but after I got persuaded to buy it
> I went out and did some googling....and found that they do have a
> reputation for picking off fish.....but my clowns are doing fine....and
> the snail losses I put down to the hermits.....

Another misconception about hermits killing snails. :-)

And again many people have seen hermits eating dead snails.
I do not know anybody seeing a hermit grabing alive and healthy
snail and killing it on the spot.

Snails do die for many reasons in the tank. Most often they die
due to the reef tanks being too hot and many snails are from the
Gulf of Mexico or some other semi-tropical but not tropical areas.
When you put animal from one environment to another it might
not kill it instantly, just significantly shorten its life.

Let's not jump too quickly to the wrong conclusion that since
hermit or mythrax was caught eating dead fish/snail it MUST
mean that the crab acturally captured the live prey....

Unless we actuallty see a helthy snail speeding on the glass
and hermit grabing it and killing I would not blame hermits...
Same applies to mythrax crabs.

We all like shortcuts when we try understand our observations.
But not all shortcuts leading to the true explanation of what happened!

You would not blame some guy "with bad reputation" for a murder
or robery only because you saw him in the store or saw him holding
dead person in his arms, would you ? Think about it... :-))

[Gill Passman]

Pszemol wrote:

> Another misconception about hermits killing snails. :-)
>
> And again many people have seen hermits eating dead snails.
> I do not know anybody seeing a hermit grabing alive and healthy
> snail and killing it on the spot.

Seen them fiddling around with my live ones....sorry....fortunately
usually the live ones manage to escape but not always.....but I guess as
with everything in the world it is the weakest that get picked off first
- so yes might agree with them not picking off the healthy.....but then
I'm not in a position to judge which snails are healthy when the crabs
go for them.....I don't know if they become unhealthy because the crabs
are attacking them or if the crabs are attacking them because they are
unhealthy....I do know that when a healthy coral frag takes a nose dive
because of the crabs what is going on.....


> Let's not jump too quickly to the wrong conclusion that since
> hermit or mythrax was caught eating dead fish/snail it MUST
> mean that the crab acturally captured the live prey....

Far from it....but lets also observe the behaviour before making any
decision......


>
> Unless we actuallty see a helthy snail speeding on the glass
> and hermit grabing it and killing I would not blame hermits...
> Same applies to mythrax crabs.

Seen my hermits do it......but that is not to say that the snail wasn't
making a last ditch attempt at survival....dog eats dog.....



>
> We all like shortcuts when we try understand our observations.
> But not all shortcuts leading to the true explanation of what happened!

I think I'm a bit like you.....I don't like taking shortcuts.....I watch
what I watch.....I make conclusions sometimes and then modify them on
the next set of observations.......part of the fascination in keeping
these little bits of an ocean in our homes....(or indeed the FW stuff
too) - there is always something to see and learn....


>
> You would not blame some guy "with bad reputation" for a murder
> or robery only because you saw him in the store or saw him holding
> dead person in his arms, would you ? Think about it... :-))

Absolutely not :-) Nor would I blame my urchins for being covered in
hermit crabs and snails for killing them......just watch the creatures
crawl away after their free ride......

gill

[TheRock]

I've seen my blue legged hermit crabs hacking into snail homes quite often.
Then after they eat them I see them wearing their shell.
You are right, some of the more healthy snails can close up until the crab
looses interest
but I've seen them wear the snail down.

Now I have enough abandon snail and crab shells in my
tank to support the next round of kids.

I don't care who eats who, just want them to keep up with the algae and
crud on the bottom. (or the occasional dead fish)


"Pszemol" > wrote in message
...
> "Gill Passman" > wrote in message
> ...
>> Well somewhere (or maybe not anymore) I have a mithrax crab in my Nano
>> tank....haven't seen it in eons.....but after I got persuaded to buy it I
>> went out and did some googling....and found that they do have a
>> reputation for picking off fish.....but my clowns are doing fine....and
>> the snail losses I put down to the hermits.....
>
> Another misconception about hermits killing snails. :-)
>
> And again many people have seen hermits eating dead snails.
> I do not know anybody seeing a hermit grabing alive and healthy
> snail and killing it on the spot.
>
> Snails do die for many reasons in the tank. Most often they die
> due to the reef tanks being too hot and many snails are from the
> Gulf of Mexico or some other semi-tropical but not tropical areas.
> When you put animal from one environment to another it might
> not kill it instantly, just significantly shorten its life.
>
> Let's not jump too quickly to the wrong conclusion that since
> hermit or mythrax was caught eating dead fish/snail it MUST
> mean that the crab acturally captured the live prey....
>
> Unless we actuallty see a helthy snail speeding on the glass
> and hermit grabing it and killing I would not blame hermits...
> Same applies to mythrax crabs.
>
> We all like shortcuts when we try understand our observations.
> But not all shortcuts leading to the true explanation of what happened!
>
> You would not blame some guy "with bad reputation" for a murder
> or robery only because you saw him in the store or saw him holding
> dead person in his arms, would you ? Think about it... :-))

[Pszemol]

"TheRock" > wrote in message news:QCCBh.1304$_O1.963@trndny04...
> I've seen my blue legged hermit crabs hacking into snail homes quite often.
> Then after they eat them I see them wearing their shell.
> You are right, some of the more healthy snails can close up until the crab
> looses interest
> but I've seen them wear the snail down.
>
> Now I have enough abandon snail and crab shells in my
> tank to support the next round of kids.
>
> I don't care who eats who, just want them to keep up with the algae and
> crud on the bottom. (or the occasional dead fish)

The whole discussion is exactly about who eats who... :-)

So it is important to notice if crabs eat dead/sick snails
or if they are able to catch/hunt down healthy snail...
In the meaning of a word "hunting" we are used to when
talking about, for example, eagle grabbing a rabbit...

For an eagle it does not relly matter if a rabbit is sick,
if it can see it, it will take it when hungry...
This behaviour I call hunting. With crabs/hermits the prey
animal has to be originaly very weak/sick or dead already
to became prey. That is why they are called "cleaning crew".

They do not decimate healthy population of snails, rather
pick the dead/sick ones as food. That is my working theory :-)
And current reports on the internet are not describing any
hunting behaviour, rather people see crabs eating dead meat
and ASSUME what must have happened before... :-)))

[TheRock]

"Pszemol" > wrote in message
...
> "TheRock" > wrote in message
> news:QCCBh.1304$_O1.963@trndny04...
>> I've seen my blue legged hermit crabs hacking into snail homes quite
>> often.
>> Then after they eat them I see them wearing their shell.
>> You are right, some of the more healthy snails can close up until the
>> crab looses interest
>> but I've seen them wear the snail down.
>>
>> Now I have enough abandon snail and crab shells in my
>> tank to support the next round of kids.
>>
>> I don't care who eats who, just want them to keep up with the algae and
>> crud on the bottom. (or the occasional dead fish)
>
> The whole discussion is exactly about who eats who... :-)
>
> So it is important to notice if crabs eat dead/sick snails
> or if they are able to catch/hunt down healthy snail...
> In the meaning of a word "hunting" we are used to when
> talking about, for example, eagle grabbing a rabbit...
>
> For an eagle it does not relly matter if a rabbit is sick,
> if it can see it, it will take it when hungry...
> This behaviour I call hunting. With crabs/hermits the prey
> animal has to be originaly very weak/sick or dead already
> to became prey. That is why they are called "cleaning crew".
>
> They do not decimate healthy population of snails, rather
> pick the dead/sick ones as food. That is my working theory :-)
> And current reports on the internet are not describing any
> hunting behaviour, rather people see crabs eating dead meat
> and ASSUME what must have happened before... :-)))

Agreed..
The ones we are talking about are not hunters.
Nor aggressive or large enough to be.

When I had a fish only tank 5 years ago (29 gal)
I had a large common hermit crab.
The one with the hairy legs...mean SOB
This guy I believe to be a hunter. He would go after everything.
My damsels used to whack him with their tails.
So to keep it REAL interesting I put 2 in the same tank.
I know, that was a dark time in my life : )

Oh the fights were incredible.

[Pszemol]

"TheRock" > wrote in message news:0zEBh.1084$SR.896@trndny06...
>> The whole discussion is exactly about who eats who... :-)
>>
>> So it is important to notice if crabs eat dead/sick snails
>> or if they are able to catch/hunt down healthy snail...
>> In the meaning of a word "hunting" we are used to when
>> talking about, for example, eagle grabbing a rabbit...
>>
>> For an eagle it does not relly matter if a rabbit is sick,
>> if it can see it, it will take it when hungry...
>> This behaviour I call hunting. With crabs/hermits the prey
>> animal has to be originaly very weak/sick or dead already
>> to became prey. That is why they are called "cleaning crew".
>>
>> They do not decimate healthy population of snails, rather
>> pick the dead/sick ones as food. That is my working theory :-)
>> And current reports on the internet are not describing any
>> hunting behaviour, rather people see crabs eating dead meat
>> and ASSUME what must have happened before... :-)))
>
> Agreed..
> The ones we are talking about are not hunters.
> Nor aggressive or large enough to be.

They are probably hunters in the regular meaning, but they
regular prey are worms, crustaceans - anything very small
they could grab with one reach of a claw. Dead/sick snail
is an opportunity they do not pass, but they usually do
not waste their life energy to hunt larger healthy animals.
At least this is my observation in my tanks, with dozens
if not hundreds of several different hermits and crabs.

> When I had a fish only tank 5 years ago (29 gal)
> I had a large common hermit crab.
> The one with the hairy legs...mean SOB
> This guy I believe to be a hunter. He would go after everything.
> My damsels used to whack him with their tails.
> So to keep it REAL interesting I put 2 in the same tank.
> I know, that was a dark time in my life : )
>
> Oh the fights were incredible.

Did they really hurt each other (broken limbs, etc.)
or just wrestle to establish who is The Leader in the tank? ;-)

[TheRock]

"Pszemol" > wrote in message
...
> "TheRock" > wrote in message
> news:0zEBh.1084$SR.896@trndny06...
>>> The whole discussion is exactly about who eats who... :-)
>>>
>>> So it is important to notice if crabs eat dead/sick snails
>>> or if they are able to catch/hunt down healthy snail...
>>> In the meaning of a word "hunting" we are used to when
>>> talking about, for example, eagle grabbing a rabbit...
>>>
>>> For an eagle it does not relly matter if a rabbit is sick,
>>> if it can see it, it will take it when hungry...
>>> This behaviour I call hunting. With crabs/hermits the prey
>>> animal has to be originaly very weak/sick or dead already
>>> to became prey. That is why they are called "cleaning crew".
>>>
>>> They do not decimate healthy population of snails, rather
>>> pick the dead/sick ones as food. That is my working theory :-)
>>> And current reports on the internet are not describing any
>>> hunting behaviour, rather people see crabs eating dead meat
>>> and ASSUME what must have happened before... :-)))
>>
>> Agreed..
>> The ones we are talking about are not hunters.
>> Nor aggressive or large enough to be.
>
> They are probably hunters in the regular meaning, but they
> regular prey are worms, crustaceans - anything very small
> they could grab with one reach of a claw. Dead/sick snail
> is an opportunity they do not pass, but they usually do
> not waste their life energy to hunt larger healthy animals.
> At least this is my observation in my tanks, with dozens
> if not hundreds of several different hermits and crabs.
>
>> When I had a fish only tank 5 years ago (29 gal)
>> I had a large common hermit crab.
>> The one with the hairy legs...mean SOB
>> This guy I believe to be a hunter. He would go after everything.
>> My damsels used to whack him with their tails.
>> So to keep it REAL interesting I put 2 in the same tank.
>> I know, that was a dark time in my life : )
>>
>> Oh the fights were incredible.
>
> Did they really hurt each other (broken limbs, etc.)
> or just wrestle to establish who is The Leader in the tank? ;-)

Oh hell no, they ended up fighting to the death !
They would start at either end of the tank banging their shells against the
glass, like a dance.
Then they would walk over to each other and start pinching and pulling, it
was a pretty even match
for a few months. They would fight, retreat and repeat.
I came home one day and the one crab was sitting at the top of a rock
completely out of it's shell. Shortly after the other crab whacked him.
Nasty SOB's. Both were 2+ inches with lots of hair and girth.

I'll tell you what, these crabs can keep a tank spotless.
Ferocious appetite, better than the reef safe crabs.
Another DeathCo...I mean Petco purchase.

[Pszemol]

"TheRock" > wrote in message news:FsHBh.1812$lG6.307@trndny08...
> Another DeathCo...I mean Petco purchase.

You must like this store a lot if you purchase so much from them ... ;-)

[TheRock]

"Pszemol" > wrote in message
...
> "TheRock" > wrote in message
> news:FsHBh.1812$lG6.307@trndny08...
>> Another DeathCo...I mean Petco purchase.
>
> You must like this store a lot if you purchase so much from them ... ;-)

They have some great deals, sometimes....I'm there for my Golden Retriever
and they suck me in !!!

The last deal I got there was some Macro Algae.
$8 for 4 very large fist full's. Red Garcinia algae

[Pszemol]

"TheRock" > wrote in message news:oJKBh.475$aM.350@trndny03...
> They have some great deals, sometimes....
> I'm there for my Golden Retriever and they suck me in !!!
>
> The last deal I got there was some Macro Algae.
> $8 for 4 very large fist full's. Red Garcinia algae

I wish Petco in Illinois, in my area would stock sal****er stuff.

[RubenD]

I don't know about crabs catching fish, but I've seen them fighting each
other. They grab each other the whole day and then I would find the pieces
of one laying on the sand. I'm talking about red leg hermits. I guess
there is always one bully in the group. Most of them are very peaceful.


Now, if you talk about my coral banded shrimp, he chase my fish, even try
to get them with his claws, sometimes with some success. Still, I haven't
seen any fatalities.

My most violent and vicious fish WERE a pseudocromis and a 3 line damsell.

Now, I'm threat free,....I think....maybe the bristle worms...nah....

Ruben


"Pszemol" > wrote in message
...
> "Tristan" > wrote in message
...
> > I still do not buy the crab did not do it. That crab grabbed
> > that fish, bad vision or not, dead fish smell or not, it seen an
> > opportunity in my eyes and took it. ;-))
>
> Judge:
> "Have you witnessed defendant killing this fish or you have not ?" :-)))

[Pszemol]

"RubenD" > wrote in message . net...
>I don't know about crabs catching fish, but I've seen them fighting each
> other. They grab each other the whole day and then I would find the pieces
> of one laying on the sand. I'm talking about red leg hermits. I guess
> there is always one bully in the group. Most of them are very peaceful.

Red leg hermits called "scarlet hermits"? The small ones?
I have 4 of them and I do not see any interesting fights... :(

Maybe you observed mating behavior just after crab molting?
And that would be the reason for pieces of old red skeleton laying
on the substrate. Crabs/shrimps mate just after molting because
they need soft bodies for the mating act, so the molting gives
a perfect opportunity for mating.

> Now, if you talk about my coral banded shrimp, he chase my fish, even try
> to get them with his claws, sometimes with some success. Still, I haven't
> seen any fatalities.

I have never had this kind of shrimp.
It was always too scray-looking for me to add it to my tank :-)