Tropical Fish Keeping - Aquarium fish care and resources

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LyzzaRyzz 05-27-2012 06:47 PM

Threads or advice on crayfish?
I just got a two an a half inch crayfish.

Are there any common threads with information, or any of you guys have any information or advice?

Id like to thank you guys for all the help and techniques you've shared with me recently!

Olympia 05-27-2012 06:51 PM

Do you know what kind?
I kept river crayfish from near my house once. Provide tons of cramp hiding spaces. Mine cannibalized each other during moulting. :(
The orange dwarfs are much friendly towards one another I hear.

LyzzaRyzz 05-27-2012 06:57 PM

Actually, I don't. I haven't taken a picture yet, and I'm having trouble uploading pictures in general to the site.

He's adjusting very well, in a five liter long plastic tub, with pots and a floating level, and some plants. His tank will be here soon.

He sleeps in the pot, clings to the bottom of the floating thing, and marches around like he owns the place

LyzzaRyzz 05-27-2012 07:00 PM

He's already eating worms from tweezers! I figure I should cut up the peices, but I don't want it to get super seems cleaner when he just eats it like a sausage..

How often should I feed him?

I fed him a moth that I caught, is that okay food? He seemed to really like it..


Olympia 05-27-2012 07:11 PM

They can eat pretty much anything so yes a moth is fine. They're fine eating things that aren't cut up, that's what the big claws are for. :-D
How often to feed, I am not totally sure. You can try feeding daily. They will usually start to fast before moulting.
You can tell sex by their bellies. Apparently it depends on the species so here are some photo examples (lol at the link name):

jaysee 05-27-2012 07:40 PM

All crayfish (with the exception of marmorkrebs, I hear) will cannibalize each other if there's not enough space for them to cohabitate, even the dwarf species IME. I would not try keeping 2 together in less than a 4 foot tank. For the dwarf species, 2 in a 10 ought to work, with more in larger tanks.

They are excellent escape artist, so it's very important to have an effective top. IME they don't try to escape from larger tanks, though they can climb heater or other cords. A heater is not required, but can be used to keep the water in the low to mid 70's if you are keeping them with fish.

Because crayfish can only utilize surface areas (mostly the footprint), they really need at least a 20 high. A 20 long would be terrific for a species tank - a 29 to keep them with fish. It's important to provide space for fish that will live with crayfish without being eaten. The smaller the tank, the more the fish are within the crayfish's grasp. Pun intended. There are some fish that are better suited to such a tank than others. I have successfully (virtually no predation) kept them with several barb species, as well as fish that stay in the upper half of the tank.

Plants are a waste of time for the full size species. I call them aquatic bulldozers - the ones they don't eat they will uproot.

They have no need to ever leave the water, so providing an island is not necessary. In fact, providing one could facilitate their escape.

LyzzaRyzz 05-27-2012 11:20 PM

I don't plan on getting another one, and I'll keep him in a species only tank next to my desk.

How fast do they grow? How old is mine if he's 2.5 inches long?

My cray fish is already climbing and exploring, so I figure I'll make a layered sort of habitat, the footprint size I have available would be 14x17 inches.

You say they'll eat all plants, that means java moss and marimo balls?

I was told that crayfish can get oxygen from the air, so if I didn't have an air stone in the tank, he'd just crawl out and get enough oxygen.

Would a simple sponge filter add enough air into the water? Or do they specifically need an air stone?

jaysee 05-28-2012 12:00 PM

Mosses are probably your best bet for plants. Leafy and rooted plants don't do well, though there may be some like java fern that might do okay as well.

Yes, crayfish, lobsters and crabs can all utilize atmospheric oxygen....if they have to. But it is not something they need, or will try to do, under normal circumstances. A filtered aquarium will provide enough oxygen that an air stone is not necessary.

Air stones add oxygen to the water by the bubbles bursting - breaking the surface tension, allowing the gas exchange to occur. The bubbles themselves, in the water, add only a minimal amount of oxygen, if any at all. The shorter the tank the less of an effect it will have in that way. The other thing that air stones do is move water.

As the bubble rises, it creates a vacuum behind it, which draws water in behind it. That's how a sponge filter works. So, the only difference between an air stone and a sponge filter is a sponge. They need a filter, so I would do a sponge instead of the plain air stone.

Olympia 05-28-2012 05:24 PM

Woops, I was talking about them eating each other earlier because I thought you said you got two half inch ones. Turns out you got one two and a half inch one.

Not sure if this is true, but I was looking into them more last night, and I read that if the crayfish has been out of water for a while not to put it back into a tank, because it needs time to adjust between atmospheric and diffused oxygen. A shallow area with access to both so it can adjust at it's own pace.
I would keep him in a full tank of water as well. I've never seen a wild crayfish out of water, I think it's something they can do in desperate times if they get stuck in a small body of water.
A good high current HOB/sponge filter will do the same job as air stones. :-D

FuelingFire 11-26-2012 03:10 PM

I Know about wild crayfish, i have seen them walk out of water, the reason being is not enough oxygen in the water, And they are cannibals if not given proper space. I have seen wild ones attack and eat smaller ones. But i can't comment on the type of species you buy at the LFS. Only ones that i have observed in the wild.

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