8 Dec 2002

Normal Behavior for Baby Crayfish

Dear Blue Lobster:

What is normal behavior for a baby crayfish? The babies hatched ~1 week ago and now they stopped moving, turned onto their sides and have turned red. Are they alive? Is this normal? What should we do? What do the baby crayfish need to eat?

Dear Gentle Sir:

It is with a heavy heart that I inform you that the state of your baby crayfish (called craybies in scientific circles) indicates that they are, sadly, expired. Moved on to that big freshwater tributary in the sky. Dead.

To directly answer your question, however, typical behavior and appearance of craybies is as follows. For the first week after hatching, they will stay on their mother's underside, and eventually grow bold enough to explore on their own, though always returning to their mother. After another week or so, they will be off on their own, independently foraging for detritus on your tank's bottom.

I wish to express my deepest sympathies and regrets to you, gentle sir, and hope that you can grow beyond this holocaust of dead baby crayfish scattered all over your aquarium and one day attempt to live again without the constant gnawing guilt of a thousand weeping souls.

You, and your silenced children, are in my prayers.

4 Dec 2002

Electric Blue Lobster Tips

Dear Blue Lobster:

Hello, I have just recently bought an Electric Blue Lobster , and I am trying to find out how to care for it better. The pet store in which I bought him at was not very helpful. I have him in a 5 gallon tank filled with water (I got the gallon sized bottled water) with some rocks, and his food, which are some shrimp (go shrinp) and a feeder fish. I got the e-care book, but it only gives refernce to Crabs. What size tank should I get, does he need heated water, a misting bottle, air pump. I don't know much from what they told me at the pet stor. What is molting also. I know this seems like a lot but, I have been everywhere for this kind of information. Please help. Thank you. Happy Holidays!!

Dear Gentle Sir:

Generally, the larger an area you can give your Electric Blue Lobster (probably actually either a procamabrus alleni or an orconectes immunis), the better. That being said, for practical purposes a 10 gallon take will suffice for the single specimen and a 20 gallon tank would be ample.

The water in the tank, which optimally should be seasoned for a few weeks before you introduce the cray, must be free of all sanitary chemicals. Chlorine and chloramine, often found in tap water, are cray-killers. A temperature of 70 degrees with a pH of 7.0, or neutral, will make for a very stable and comfortable environment for your blue lobster. An air pump of some sort should be used in the tank, if not a substratum filter. Oxygen is important to crayfish.

As for molting, good sir, it is the natural process by which crayfish (as well as other crustaceans) shed their hard exoskeleton in order to grow. The process is preceded by strange eating behaviors and activity patterns. The shell will split at the carapace and the cray usually escapes through the top of the tail. During this stage the lobster is vulnerable and will hide for a few days, and is why it is important that there is plenty of space and hiding places in the tank: predacious fish species as well as other crays will consider the molted lobster as prey! After hardening the new, larger exo-skeleton, the crayfish should begin eating normally. You may also notice that any missing or injured limbs have reappeared in some manner after the molt.

The Embrace Question

Dear Blue Lobster:

I have two crayfish in my African cichlid tank. One is blue and has longer claws (if that's the right term), and the other is brown and has shorter claws. Do the size of the front claws indicate male and female? They have been together in the tank for a few months. Twice I have seen the longer-clawed crayfish (blue) grab hold of the shorter one's claws and hold it in what looks like a mating embrace. Could this actually be a mating embrace, or are they probably just fighting? Thanks.

Dear Gentle Sir:

To address the most important point first, no, what you are observing is not a mating embrace. It is an embrace of death, brought about by territorial disputes between the two crayfish in your tank!

I recommend either relocating one of the two crayfish, or moving the entire system to a larger tank. Crayfish are territorial and what you have seen in the past is a guarantee of oblivion for the first of these two arch-rivals the moment that they molt and become vulnerable!!!

As for the question about claw size indicating gender: no, sir, this simply indicates that these crays are of different species, and most probably different genera as well.

2 Dec 2002

My Fiddler Crab Is Losing His Legs!

Dear Blue Lobster:

please help my fiddler crab is losing his legs!i just got him 2 days ago and he is eating and acting fine (except for his leg) i also keep him in a 10 gallon tank with 1 other male crab thank u

Dear Gentle Sir:

A 10 gallon tank may be too small to keep a pair of male fiddlers in. Just because the pet store does it doesn't mean that you should!!!

Other than stress created by suboptimal territory distribution between the two male fiddlers, here are a few other points to check up on:

  1. Are the crabs being fed properly? Crustaceans are oppostunistic cannibals, and since these two males are kept closely together, territorial disputes may become occasions for quick meals.

  2. What's the water like? Check pH, temperature, and nitrate levels, all of which can affect fiddlers. Also make sure that if you used tap water for your tank, you removed the chlorine or any other sanitary chemicals from it first.

  3. Can the fiddlers get out of the water? In a 10 gallon tank, the water should be no higher than 3", with several areas the fiddlers can climb out of the water at. Fiddlers need air! Without access to air, a fiddler's health will decrease.

  4. Hiding places! Like crayfish and lobsters, fiddler crabs molt. When molted, their hard exo-skeleton is shed off and they are left vulnerable for a few days while they recalcify their new exo-skeleton. Without a place to hide while so weak and soft, they can easily lose legs from competing fiddlers or any other predacious species in the tank.

28 Nov 2002

Cherax Trouble

Dear Blue Lobster:

I recently acquired a cherax speciman, air-mailed from Australia last week. Since then I've had the cray in a 50-gallon freshwater aquarium. The water was seasoned from known-safe tap-water, since I didn't feel using creek water containing local microorgasms would be safe for the cherax. Feeding him bloodworms, earthworms, and lettuce the cherax seemed fine until this Thanksgiving evening.

Returning home with several tubs of leftovers from a Thanksgiving dinner, I proceded to feed my cherax some chilled, roasted turkey (in 2mm strips), mashed potatoes (by means of a cotton swab) and gravy (through an eyedropper). Sirs, after feeding him this meal I left my aquarium room for several hours — and returned to find my cherax in his current state!

My cherax is now lying on his side, twitching, with a string of dark fecal matter trailing from its anus and several strange, white beads of mucus oozing from its mouth-parts. I immediately checked the water for pH levels and nitrids and found the results to be not only well within acceptable limits for the cherax but also identical to my last such test made 16 hours prior to this one. Increasing the intensity of the flow to and from the filter and increasing oxygen levels in the tank seemed to ease the twitching but the cherax is still mostly inert. At this moment its only activity is gill-fanning and the occasional eye-cleaning movement.

I've seen molts begin like this (aside from the feces and mucus), but at this stage in the process the carapace should have split by now, and there is no indication of such with my cherax. There are also no signs of acute parasitic infestation. What could be causing this strange behaviour in my cherax? I fear it will die soon if I can not identify the problem and treat it. Do any of these symptoms seem familiar to anyone reading this forum?

Please contact me if you have any information regarding this!

Thank you.

P.S. His name is Bob.

Dear Gentle Sir:

It sounds like your aquarium environment is sound and it's safe to assume that Bob is not molting as the fecal matter should not be trailing from his anus at this point. We shall instead focus on Bob's last meal, an ironic "thanksgiving" if ever there were one.

The holiday menu appears to have been quite healthy: a meat (turkey), a starch (mashed potatoes), and a fat (gravy) in small, well-balanced portions equal to his size and dietary needs. Most crays would be lucky to get even shrimp tails after New Year's Eve, let alone a down-home thanksgiving meal. One might surmise that Bob, a lowly invertebrate held in the same esteem as a mosquito or a late-night snack, is simply dying of happiness.

Barring such a comfortable death, which is sadly unlikely, a few other possible causes may exist, each more insidious than the last.

Copper, known as Cu in the periodic table, is a soft metal used to kill invertebrates. In some cultures the family meal during holidays is cooked with copper. Immigrants used pennies to stuff their turkey, chicken, or game hen to symbolize the wealth and good fortune they wished for their family. After taking the copper out of the bird, the flesh was still saturated with high levels of the metal.

If your family cooked the turkey in this manner, you may have unknowingly introduced copper into your tank which then killed your cray. if this is true, then God help you.

Another possible explanation is Crayfish Plague. This disease eats at the cray's shell and soft innards, eventually resulting in the cray's death. Potatoes grown in Ireland often live in flooded fields where crays take up residence in the late Spring. During this time the potato crop would have absorbed the plague, harmless to the plant and humans but deadly to your cray when fed the mashed tuber. Check for spots on your cray's shell.

One last thing to consider is food poisoning. Did you or anyone else at your family dinner feel ill after the meal? Do you know for a fact that all of the food was cooked properly and handled by clean hands? Salmonella poisoning is responsible for more food-related illness than all other causes combined, and your crayfish is vulnerable to it too. E. coli could also be the culprit if someone didn't wash properly after defecating and may explain the "diarrhea" your cray is exhibiting.

Sadly for you, sir, I would guess Bob is dead by this point. It will be a very lonely holiday season. My condolences go out to you and your family during this dark time.