Question about my crayfish...

Factual Questions
1

So I have a blue crayfish in my aquarium. I have had him/her for at least 2 years (maybe close to 3). When I bought it, it was about 1.5 inches long, now it’s close to 6 or 7 inches long.

Anyway, about 4-5 days ago, it got very lethargic, it was laying on it’s side a lot. I took this as a sign it was kicking the bucket. It did this for 2 or 3 days, then it spent the next 2 days under a brick I have in the tank.

During this time he did not eat.

Last night I look in the tank and he/she is motoring around the tank. I notice a couple of my neons are missing and one other fish that I forgot the name of (about 2.5 times the size of a neon tetra with black and gold horizontal stripes). Then I see him/her burning around and there was about 2 dozen creamy whit things under it’s tail. I call my girlfriend over and before she could get there it folded it’s tail over so you can’t see them.

Now my question is, what are these things? I figure they are eggs. Now do these need to be fertalized by a male? Or do they produce asexually?

What should I do?

MtM

2

Sounds to me like your crayfish is molting…or shedding it’s skin. The things you describe are textbook molting behaviour.

3

Yeah your crayfish just molted. To go from 1.5 to 6 inches, it must have molted a dozen times or more - have you ever seen it molting? It could hide the evidence by eating the old shell as is the pattern.

The white things under the tail are just the swimmerets, and the crayfish has always had them. They don’t reproduce asexually, it takes two baby! The eggs are usually dark and in a cluster under the tail… the look like a big blackberry .

4

I have seen him molt a few times. I don’t think he has molted this time, usually there are always bits left over that he hasn’t eaten yet.

I can garuntee what I saw were not swimmerets, I have seen them many times.

So I’m thinking they must be eggs. What will it do with them?

MtM

5

The black/gold fish sounds like a zebra danio.

If your crayfish has gone from 1.5 to 7 inches, it’s definitely molted plenty of times. Is its current behavior significantly different from the previous times?

I know that american lobster females are (usually) only fertilized directly after molting, so the fact that its current behavior is like its molting behavior may not be surprising, since american lobsters and crayfish are all within Astacidea. (Random note: American lobsters copulate in the missionary position)

From this site: “Female lobsters extrude their egg masses whether or not they have mated.” http://www.lobsters.org/ldoc/ldoc1100.html
So that seems pretty definite for them.

From TH Huxley’s book on crayfish:

“When they leave the oviduct, the ova are invested by a viscous, transparent substance, which attaches them to the swimmerets of the female, and then sets; thus each egg, inclosed in a tough case, is firmly suspended by a stalk, which, on the one side, is continued into the substance of the case, while, on the other, it is fixed to the swimmeret. … Ova to which spermatozoa have had no access, give rise to no progeny”

It sort of implies that unfertilized eggs are extruded and attached, but the ellipsis I’ve used chops out a whole lot, so who knows. The whole book’s online:
http://www2.biology.ualberta.ca/palmer/thh/crayfish.htm

Oh, also, egg-bearing females tend to be ravenous, which could account for your fish going missing.

And, btw, may I just express my admiration for you for having a cute little crustacean as a pet. Yay!

6

It’s pinin’ for the Fjords! The American Blue crayfish likes to kip on 'is back!:slight_smile:
I am intrigued about the whole pet crustacean thing, I have a 10Gal tank with 4 danios and 3 swordtails, I’ll have to ask at my local pet shop about getting a shrimp or a crayfish…coolness!

7

Re: the disappearing neons…

I had an albino crayfish in my aquarium for a little while. It seemed to get along fine with my neon tetras. Then, one by one, they started disappearing. One morning, I found a half-eaten one on the gravel, with the crayfish sitting at the other end of the tank, innocently waving its antennae and fluttering its mandibles.

Crayfish are nocturnal. You won’t see them eat your fish, but they’ll do it when you’re sleeping.

Sounds like your blue may have been visited by the Angel Gabriel of crayfish…

Kin you say ‘parthenogenesis’? Sure you can!

8

Crayfish are parthenogenetic? Cool! I suppose the fact that I was quoting from a book published in 1880 explains the contradiction. :slight_smile:

I used to have a pet crayfish, he never caught one of my fish, but he’d make grabs at them all the time. (These were $10 congo tetras, so I was a bit worried) I eventually took him back to the pet shop; he was chopping up all the plants in my tank. I shoulda just gotten plastic plants, the crayfish was adorable.

9

I hear you Sengkelat, this is my third crayfish (first one commited suicide, second one died of old age).

My second one was given to me by somebody at work because they no longer wanted it. I had about $50 on plants in my tank, and the cray fish took care of them in about 2 days!

MtM

10

We donated our crayfish to our daughter’s school after it ate its second angelfish. (Okay, first I moved it into solitary in the 2.5 gallon tank we had used for betta breeding. I grew another inch or so in there, and I don’t believe I fed it during that time. I was afraid we were doing a remake of the classic 1980 movie **Island Claws **.)

11

:smiley: :smiley: :smiley:

So…

How many inches are you now?

:smiley: :smiley: :smiley:
Sorry! I couldn’t resist!

12

So how is Pinchy doing?

13

Pinchy is pretty much the same. She (I’m assuming they are eggs) goes out and about every once and a while. But she has been hiding out quite a bit under her brick.

I’ve been hoping to snap a digital picture of her with her tail extended so you all can see what I saw under the tail, but she’s been keeping her tail curled under her.

MtM

14

Yay crustaceans!

They are great tank buddies. We have a freshwater Singapore Shrimp right now that is fantastic. It is a couple inches long, has long wavy whip antenna, and four little “hands” with these cool filter-fingers that it fans the water with to filter out food. The best part is the adorably cute way that it slurpity-slurps the food off of its hands.

Shimp/Crayfish are generally very hardy and long-lived, come in fresh and salt varieties, and are nice and non-agressive.

Looking to get a blue crayfish soon…

15

So here is my next question, if my cray fish reproduces asexually, what will she do with the eggs?

Will she burry them? or keep them attached to herself until they hatch?

I ask this beacuse her tail is folded over bigtime, I’m thinking to protect the eggs.

Does anyone know what the gestation period of a crayfish egg would be?

MtM

16

When they hatch they will be all over the tank, until your fish eat them. She will carry them till they hatch.