Marmorkreb Keepers in the House?

[Trouser Bark]

I've wanted to raise Marbled Crayfish since not long after they popped up in a German aquarium a few decades ago and now is that time. I set up a 60G tank for them and have several en route. What I don't find is much information on them and of what I have found much seems subjective and maybe like the author's heart was in the right place but they said things that have since become different from the author's claims.

There's an article on this site that mentions Marmorkrebs and states something about how others unfamiliar had exaggerated the potential hazards associated w/ ownership and since that person's thoughts were penned several rivers in Europe have been devastated and in much of Europe they're now banned.

Does anyone here have experience w/ them? I've heard everything from how they're gentle and don't harm each other like other crays to 'oh yeah they're cannibals, escape artists, natural born killers and super sensitive to water parameter changes'.

Anybody here got 'em? Do you successfully raise their young? Any thoughts that a newb should bear in mind?

 

[Trouser Bark]

Well, looks like we might be coming in blind and hot.

The tank is a 60G Tall (@ 48"L x 12.5D x 24"H) set up and operating but w/ no crays yet. There are a half dozen fat head minnows and a single Endler fry in the tank to feed a bacterial pad and there's a 2" diameter x 4" long airstone that's creating quite a bit of movement in the water as it's fed by a DAPMH15 from Jehmco... and yeah, there are other stones and other tanks connected to that same pump or the stone would be flying around bashing into stuff. That compressor is curiously quiet and capable. The bacterial pad and airstone will be replaced w/ cube filters from SwissTropicals.com soon. I'll drop the water level to 2" from the top once the crays arrive so they can't get ahold of anything above the waterline and boost their way out for an adventure.

Tonight I'll cut a few 5-6" sections of 1.25"-1.5" PVC tubes and toss a couple pottery shards in to make something like shrimp cabins and w/in a few days we should be off and running. I'll use this section to document successes and failures.

I have kept colonies of Neocaridina before and have a few hundred of them now. I currently have a small colony of orange Mexican Dwarf Crays and a couple decades back I had an Electric Blue Cray that was an unpleasant individual. If you looked up aggressive cornhole in the dictionary you'd see a pic of a blue cray. No more of those bad boys for me.

I'm expecting that these marbles might be a little more relaxed and less inclined to take a swing at everyone else in the tank than old blue had been. Neos and Mexican Dwarves seem to get along well and if they don't I've never noticed a problem among them despite the fact that they share a tank.

Marmorkrebs are parthenogenic. All are female and there is no such thing as a male. They clone themselves and are suspected to be an example of Rapid Generation of Species. I would not own them for ethical reasons if I felt there might be a way that any of them might get out of the fish room. I live in the mountains at 61*N where nature is inhospitable and creeks freeze solid every winter for months on end. Be that as it may there are indications that marbles can devastate river ecology in hospitable environments and ownership has now been banned in most of Europe, parts of the US and in other countries as well.

They're en route to me as of this morning.

 

[Deadeye]

Good luck!
I haven’t kept these guys but I would suspect care isn’t too far off from any of their relatives.

 

[freebyrd]

These are interesting. Please keep us updated. show us some pictures!

 

[Fallen_Leaves16]

Think I kept them years ago; they're able to be kept in groups, but still squabble a fair bit; nothing to the point of significant limb loss or death of another, though. Good climbers, as most crayfish are. Not picky about what they eat, but less inclined to take terrestrial vegetation. Especially fond of dead fish, somewhat decent at catching live fish if given the opportunity.
Just about impossible to kill; had some that crawled out of the tank and kept finding desiccated crayfish bodies scattered about in obscure closets and corners, oftentimes hundreds of feet away from the tank. Even found one on the lawn; can't figure out how it got there. Tolerated a general range of water parameters; nothing very soft, though. Hard water tended to lead to a high egg mortality rate. They do breed like rabbits, though the eggs can be pulled and killed if desired, and the young are cannibalistic and tend to help manage their own population.
I don't know if I'd use them as feeders, as a colony (I had ~7) isn't that productive; maybe about as much as a small group of bristlenose plecos. Which is still rather productive, just maybe not very sustainable as a staple.
Cool little things, though I'm still more fond of PNG Cherax.

 

[Ansorgii]

I kept them as a kid, someone gifted me two for my birthday, and in retrospec, that was a really bad present.

One of them died shortly after, and the other started reproducing after a few weeks. And from that day on till the Aquarium was set dry I never got rid of them. They kept reproducing like crazy, and no matter how much you tried to remove them somewhere a few tiny ones survived and repopulated.

They ate and killed everything, including occasionally each other. Only large fast fish and plecos were to tough for them to keep a hold on.

I kept them at room temperature in an Aquarium full of rocks and cyperus gras, which they loved to hide in and use to climb out of the tank. The water quality was what you would expect from an 8 year old.

I can totally see why they would be banned anywhere and hope that I did not start an accidental population in my area.

If you really wanna keep them, there is no reason to worry about your setup. Just maybe pick sth with more variation and a less smooth surface than pvc tubes. If you wanna breed them offer the small ones plenty of hiding space.

 

[Trouser Bark]

Houston, we have liftoff.

 

[Trouser Bark]

I kept them as a kid, someone gifted me two for my birthday, and in retrospec, that was a really bad present.

One of them died shortly after, and the other started reproducing after a few weeks. And from that day on till the Aquarium was set dry I never got rid of them. They kept reproducing like crazy, and no matter how much you tried to remove them somewhere a few tiny ones survived and repopulated.

They ate and killed everything, including occasionally each other. Only large fast fish and plecos were to tough for them to keep a hold on.

I kept them at room temperature in an Aquarium full of rocks and cyperus gras, which they loved to hide in and use to climb out of the tank. The water quality was what you would expect from an 8 year old.

I can totally see why they would be banned anywhere and hope that I did not start an accidental population in my area.

If you really wanna keep them, there is no reason to worry about your setup. Just maybe pick sth with more variation and a less smooth surface than pvc tubes. If you wanna breed them offer the small ones plenty of hiding space.

Top drawer post. Thanks for sharing. I will pepper the bottom of the tank w/ golfball sized rocks so the little ones can get away from the big ones and I'll toss a little more variation in the tank for hotel rooms.

 

[Trouser Bark]

All of them rec'd in their own individual bags except for one bag that had two. One of them was The Highlander and disposed of his traveling partner en route.

 

[Ansorgii]

Houston, we have liftoff.

View attachment 1528569

The crayfish has landed

Take more pointy/square rocks than round if possible