FW Crabs
Hello again. Thanks for taking a look at my letter. I have a few more questions for you. Using the German crab ID page I found on your site, I have determined that my soap dish crab is the third Thai fresh water crab they have listed, it looks just like my little Carl, right down to the dark zig-zags on his appendages. It says it is of the Demanietta species, but that seems to include a lot of different looking crabs. How can I narrow it down further?
< Do a Google search on the web using the Demanietta species you have already found. That should get you closer to a correct ID.>
Anyways, I've started adding iodine to all my crab tanks. How often should I add the drop? daily?
< Add the drop of iodine every time you change water.>
The water I use is well-water with a softener. If this is no good, what type of water should I use? Would adding some sea shells add calcium to the water?
< All crabs like brackish water. I would use the softened well water but add some sea salt and micronutrients at about 1/3 to 1/2 the dosage recommended for salt water.>
I know the fiddlers prefer brackish water, does Carl need some salinity also?
< You bet.>
Should I change the water to brackish?
< The sooner the better.>
Would his feeder minnows tolerate the salt?
< They are pretty tolerant to salt and would probably do OK.>
He has not molted since I have had him, but I just figured he was big enough that he only molted once a year. Am I incorrect with this assumption?
< Sounds like a pretty safe assumption.>
How big is this guy supposed to get, anyway? What is this creatures lifespan?
well, thanks in advance, Scott
< They usually get about 2 to three inches across the body and will probably live between 2 and 5 years depending on how old Carl was when he was caught.-Chuck> 

Crabby Confusion - Playing With Common Names - 10/11/2004
I recently ran across a Red Thai Crab in my LFS.  
<Hui.  With so little English information on crabs offered in the aquarium trade, I fear "Red Thai Crab" is just about as descriptive as "Small, colorful fish" to describe a neon tetra....  Not your fault at all, just the fact of the matter.>
I have never seen one before.  It was huge and in fresh water, and obviously red.  
<Well, red helps quite a bit.  Getting' some ideas, at least.>
I have no idea what the scientific name might be,
<Sad.  But not unexpected.  I haven't seen a single crab available for sale with a Latin name for a label.>
and my search on the internet has proven well, let's just say made me hungry, I can now prepare crab 100 different ways.
<Great!  You can come make dinner, then!  ;) >
Now the meat of the email.  
<The crabmeat, as it were.>
I have a brackish water tank with a Snowflake eel, a dragon fish, and some Sailfin mollies.  I would like to add one of these crabs to the tank but......  I have no idea if it is truly a freshwater crab and more importantly will it eat my eel and dragon fish.
<Well, let's try to explore *what* this crab is.  Also, a tank size would be of some assistance - also, I'd like to drop a bit of a hint that your eel may prefer saltwater as it matures.>
Does it require a spot to get out of the water on occasion?  The size of the crab was a good 4 inches, could be bigger it was busy moving a large rock in the tank.  
<Alrighty....  You say "obviously red", easily 4", and sounds like a bruiser to be redecorating his digs.  My first, best guess is Gecarcinus ruricola (possibly the genus name is spelled 'Gercacinus'....)  Please see here: http://www.wirbellose.de/arten.cgi?action=show&artNo=115 .  I have seen this species offered for sale quite a few times, now.  Some problems with this animal - and *especially* in keeping it in an aquarium - to my understanding, this crab, surprisingly, is not very aquatic.  In the wild, it rarely enters the water, and instead gets its moisture mostly from humidity in the air.  To keep it totally submerged is a short life sentence.  It should be kept in a terrarium with enough water available to be fully submerged should it choose to do so (for instance, low humidity).  The water available can be plain ol' freshwater, but I think it might be prudent to offer a separate container of brackish water, as well.  If I recall correctly, this crab gets big - roughly an eight inch leg span - and though not horrifically aggressive, I'm sure it would willingly pick off small fishes or land animals.  Feed with aquatic meats, also non-citrus fruits and veggies should be offered.  There is an Aqualog book by Uwe Werner available that has a (small) section on this crab.>
My eel is about 18-19 inches long (of pure hunger) and the dragon fish is about 13 inches (odd fish there), neat how that fish eats.
<Neat indeed!>
Also I just bought a 150 gallon tank for my brackish system (have not changed it over from the 55 yet) Just how big will that Snowflake eel get?
<Big.  Quite big.  I urge you to see here:  http://www.wetwebmedia.com/FWSubWebIndex/fwmorayeels.htm  and make use of http://www.fishbase.org as well.  As you will see, much is dependant upon specifically what fish you have.  Whatever your eel is, a 150 should be adequate; it's mostly just a matter of determining what kind of water it will need as it grows.>
It was only like 5 inches long when I bought it and it just grows and grows and grows, oh and it eats and eats and eats, I love it.
<Glad to hear it.  Amazing animals, aren't they?>
Thanks you guys for any info you can give me.
<Please do write back if you wish, especially if my guess on the crab in question was off - a very detailed description of color, placement and size of the eyes (widely spaced? long eyestalks?), whether one claw is significantly larger than the other, and any details you can muster will help.  And, of course, a picture is worth a thousand words!  Otherwise, you might be able to ID the feller here:  http://www.wirbellose.de/arten.html#Krabben .>
Craig in Peoria ILL
<Wishing you and your fantastic fishes well,  -Sabrina in Boulder Creek, CA>