Crayfish in a community tank?

[equinom]

What does everybody think about crayfish in a peaceful community tank?  I've heard a variety of things - not surprising - ranging from
a)  they help keep the gravel clean by constantly moving it around, causing wastes to have a better chance of getting filtered
b)  they will eat all the fish

What do you think?

 

[geoffgarcia2]

the smaller they are the more aggressive.
When they are under like 3" they will climb on everything in your tank, from undergravel filter tubes, heaters, plants, you name it then they will jump off and try to land on fish which is hilarious to watch. Most fish sleep on the bottom, and they are easy pray for a crayfish. To remedy that I simply clipped off the thumbs on their big pinchers. Most people think this is cruel. Its not. They have 2 pairs of forearms, 4 pairs of legs and 2 pairs of pinchers. unless your feeding it live food (aka your other fish) they don't need these claws, so remove the thumbs is the best answer. They will grow back smaller and will never be a threat again.
PS-they are awesome in a community tank

 

[equinom]

What do you mean by "awesome"?  Do they actually help clean the tank?  Just curious.

My son had been begging for a crayfish - so I went ahead and got one.  I think it's about 3 inches.  I have seen it climb up a plant and try to jump - it was too funny!  

But I did notice that we are down one zebra danio - which I find hard to believe because danios are so fast...  And yes, I am feeding the crayfish shrimp pellets in addition to the danios.  Is there a better food?  As soon as I drop in the pellet the crayfish comes right over and grabs it - I only give it one pellet because I don't want extra waste.  

The crayfish seems to spend most of it's time under a log that's in the tank - when I look in there to find it, it runs out and waves it's claws at me - as if I was a threat.  Eat another fish and I will be a threat!   *laughingcryingsmiley*

Just how hard is it to "cut off their thumbs"?  It was missing one front "leg" when we got it.  Doesn't seem to bother it.  How should this thing be held during it's operation so as not to get pinched?  

 

[equinom]

That's it - now I'm really mad!  It ate the turquoise gourami!!!

Actually last week I thought we lost the crayfish - but it had only "shed"  it's old shell.  Wish I had been there to see it - would have been great for my son to see that.

But when I caught it with the turquoise gourami still in those damn claws, and the fish almost completely eaten ---  >

So those thumbs are coming off!   *thumbsup2*  
Makes me think of that scene in "The English Patient"

 

[colesea]

It might be better if you just remove the whole claw rather than try to take the "thumb" part off. This'll probably take two people.

1) Remove crayfish from tank, use a net, probably easier

2) Grasp him from behind, on the thorax (aka carapace). It'll probably flap its tail around at you, don't get frightened and let go. You can usually keep the tail from flapping if you can get your pinky around it (I'm used to using a one handed method where you grab the carapace between thumb and forefinger, and used the rest of your hand to curl around and keep it from flapping).

3) Flip the little sucka over on his back

4) Grasping the large claw gently, kinda just, twist it off, like you would remove a lobster or crab claw. *hmmm......steamed blue crab...drool*

This is where it is probably easier to have one person hold the sucker while the other person twists the claw off.

5) Repeat second claw

6) Return him to the tank

I don't know if this process "hurts" or not, I'm not exactly sure how crayfish register pain, but it is pretty normal for a crayfish in the wild to loose one or both claws to a predator, or rival in a fight.  They are adapted to drop the limb if it becomes a hinderance to the life of the whole animal. They do not eat with these big claws, they are primarily used, as you have discovered, to catch food, attract mates, ward off rivals, and display of that nature. Of course, the everyone knows the claw is where the best meat is...*hmmm....cajun style crawdads....drool*. Shrimp pellets are a fine food, you might want to subliment with an algae waffer now and again as well. Crayfish will eat just about everything.

They will grow back though. Upon your crawfish's next molt, you'll see he has new claws again, and you'll have to remove them again.
~~Colesea

 

[aznpanther98]

i use to have a crayfish in my old 30gal(long before i started on plants) well i didn't put it in my father did when he bought crayfish about 3" in length from some fish market near the cheasapkeke bay
well anyways he thought he'd put one into the tank and i thoughtit was cool fed it shrmppellets every day even saw it molt i thought it died at first b/c it had a hole on the end of it's tail and then saw another cray but without the hole, at that time i had a upsidedown catfish, couple of swordtails, three gold gouramies, and some cory cats well anyways i saw it one day eatingmy upsidedown catfish and it pissed me off i like the catfish and it was the most unusual fish i saw at that time... well it made me mad b/c it was hard to find in petshops in my area and i took the crayfish out and put it into a bowl for a few weeks until it died while molting.but oh well my dad got a pound oof crays for like 6 bucks or something like that
*celebratesmiley*

 

[equinom]

I chased him around the tank, and finally pinned him down - really enjoyed that.  What I ended up doing was to hold it against the side of the kitchen sink using a slotted spoon.  For some unknown reason he stuck his claws through the slots...  and I just clipped off the smaller part of the claw.  

Have to say - today he looked pretty meek - not threatening at all.  Maybe the claw is the "seat of knowledge" for crayfish... he looks like he's been though a lobotomy.

Before I put him back I checked the water - nitrites were present.  Could that have been from his killing/eating of the gourami?  I did replace the filter after finding the half eaten fish (it was time to anyway).  I did a small water change and it's OK now - but the water chemistries had been good for a while.  Haven't added new fish.  What could have caused this change in the nitrites?

 

[geoffgarcia2]

no idea about the nitrates.
My first crayfish I tried removing the entire claw and it died within 24 hours either from the shock or some other aspect of the tank. Cutting just the thumb parts on my next one worked great but it did slow him down as you say....kinda like castration. He stopped climbing, and I did feel a little sorry for him, but he ate soo many of my fish....
they are about 30cents each up here