Guest FLIP Posted April 5, 2008 Report Share Posted April 5, 2008 I got a Cherax Blue Lobster today I know how big they get and the requirements they need but I have a question, my electric blue crayfish is a very friendly little guy and has never hurt a fish but it used to play fight with my featherfin catfish by just barely clamping at parts of it. Would the crayfish try to kill the lobster? I know it's probably trial and error. Val I noticed the cray you brought to the bowl show and was wondering if that was a Cherax Blue Lobster aswell seeing they look almost identicle from what I remember. Quote Link to comment Share on other sites More sharing options...
Vallisneria Posted April 5, 2008 Report Share Posted April 5, 2008 Yes, mine is a Cherax quadricarinatus. I've kept a couple different kinds of crays and I've found they are all pretty similar in that they will eat anything they can get their claws on(plants, fish, food you give them) but it's their aggression that differs. Some were super aggressive and tried to attack anything that came close to the tank and kill any fish I put in with them. While others were more shy, hid and lived nicely with fish. So personally I wouldn't put a new crayfish in with fish or plants until you know their temperament. Quote Link to comment Share on other sites More sharing options...
Slough Shark Posted April 5, 2008 Report Share Posted April 5, 2008 Try setting aside a temporary 5-10 gallon and put the new cray in it. Buy some cheap dithers (danios would be my pick) and add them to that tank, then you watch the tank and see if the cray eats any. If it eats those, then theres no way it'll be safe with slower moving bottom dwellers. My last cray left all of the rasboras alone, but exterminated my kuhli loaches. Good luck Paul, Taylor Quote Link to comment Share on other sites More sharing options...
Guest FLIP Posted April 5, 2008 Report Share Posted April 5, 2008 I read they can't catch fast moving fish so I'm not really that worried I have a few fish in with the crays at the moment but that's a pretty good idea you have. Quote Link to comment Share on other sites More sharing options...
Vallisneria Posted April 5, 2008 Report Share Posted April 5, 2008 Some crays can catch fast moving fish. My last one would catch zebra danios without a problem. Quote Link to comment Share on other sites More sharing options...
Slough Shark Posted April 5, 2008 Report Share Posted April 5, 2008 My technique is good for revealing just how aggressive the cray can be, what I mean by it is that if it kills the dithers you pu in the "test" tank, than you can rule out basically any other tankmates. I did this with my last two crays with success. But my first cray was a cherax destroyer- exactly (or close to) what you have, and just like Valerie's cray, it could catch quick schooling fish. So try out this method if you can, it's better to be safe than sorry! Quote Link to comment Share on other sites More sharing options...
FrogFan23 Posted April 6, 2008 Report Share Posted April 6, 2008 I got a Cherax Blue Lobster today I know how big they get and the requirements they need but I have a question, my electric blue crayfish is a very friendly little guy and has never hurt a fish but it used to play fight with my featherfin catfish by just barely clamping at parts of it. Would the crayfish try to kill the lobster? I know it's probably trial and error. Val I noticed the cray you brought to the bowl show and was wondering if that was a Cherax Blue Lobster aswell seeing they look almost identicle from what I remember. It is generally not a good idea to keep Australian species (cherax) in the same tank with North American species (electric blue). The North Am species can carry a disease to which the aussies have no immunity (the "crayfish plague"). Also, some of the cherax species get significantly larger than North Am species. A few of the aussie species get larger than one foot in length (the quad typically gets to about 10 inches). Here's a link that tells about the disease: http://grannyshouse.biz/page9.html Quote Link to comment Share on other sites More sharing options...
Vallisneria Posted April 6, 2008 Report Share Posted April 6, 2008 when measuring crayfish is it from the tip of the claws(when stretched out) to the tip of the tail? Or just the body lenght? Quote Link to comment Share on other sites More sharing options...
FrogFan23 Posted April 6, 2008 Report Share Posted April 6, 2008 when measuring crayfish is it from the tip of the claws(when stretched out) to the tip of the tail? Or just the body lenght? It's always been my understanding that you do not include the claws. I got the length from CanadianCray's website but there is no indication of whether the tail is included in that measurement. The government of Western Australia does not include the claws or tail when they measure crays (i.e., they measure from the tip of the rostrum to the back of the carapace). However, based on what I read in the Bluecrayfish forum, the hobbyist standard for measurement is nose/rostrum to tail. I wasn't able to find any clear information from Aussie sources to confirm the length of the Quad, either. But, if you check out this page, it will show the size relative to the human hand: Queensland Crayfish Farmer's Association - About the Redclaw Quote Link to comment Share on other sites More sharing options...
Vallisneria Posted April 6, 2008 Report Share Posted April 6, 2008 I have heard that some crayfish can get 8"+, so if they are measuring that from the tip of the head to the tip of the tail that is one HUGE crayfish. It would be well over a foot in length including the claws! That's more lobster sized then crayfish sized. Anyone seen any pics of these giant crayfish(with somethingin the pic for size comparison). Quote Link to comment Share on other sites More sharing options...
FrogFan23 Posted April 7, 2008 Report Share Posted April 7, 2008 Some of the Aussie species can get as big as a saltwater lobster, if not bigger. Cherax quadricarinatus is very common in the commercial trade due to its size. Some say that it tastes better than saltwater lobster. The largest freshwater crayfish in the world is Astacopsis gouldi, the Giant Tasmanian Freshwater Lobster. This bruisers can grow to a wopping 40 cm (16") carapace length (excluding tail and claws) and can weigh between 4 - 6 kg. They are an endangered species. Here are some pictures: Astacopsis gouldi Mercury - Astacopsis gouldi Recovery Plan Here is a shot of someone holding the second largest crayfish, the Murray Crayfish. It can reach a carapace length of 15 - 20 cm (6" - 8"), excluding tail and claws. They can weigh up to 2 kg. The Murray Crayfish is also considered to be good eating. Crayfishworld - Big Crayfish Quote Link to comment Share on other sites More sharing options...
Vallisneria Posted April 7, 2008 Report Share Posted April 7, 2008 Wow, thanks. Thank god my guy is nowhere near that big. I'd be scared to clean the tank. Quote Link to comment Share on other sites More sharing options...
Guest FLIP Posted April 7, 2008 Report Share Posted April 7, 2008 Well the new crayfish dissapeared yesterday it may be hiding in one of the shells in the tank but I've searched them as best as I can and found nothing and searched my room for it and found nothing could the blue crayfish eat it all in one night? (I was woken up by some splashing in the night but thats normal) Quote Link to comment Share on other sites More sharing options...
fatpuffer Posted April 7, 2008 Report Share Posted April 7, 2008 Is the cover tight? It might have escaped. My blue cray escaped from the hole for the HOB filter. Js Quote Link to comment Share on other sites More sharing options...
Guest FLIP Posted April 7, 2008 Report Share Posted April 7, 2008 There was a very small hole but it was in a very weird place for the cray to be able to get to but like I said I've looked all over the room and found nothing. Quote Link to comment Share on other sites More sharing options...
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