deeveus Posted May 15, 2005 Report Share Posted May 15, 2005 Can crayfish or any other native NZ fishes survive in tropical water? Just a crazy idea but would like to have a cray in my tank aswell, maybe even some oysters and blue cod. Quote Link to comment Share on other sites More sharing options...
reef Posted May 15, 2005 Report Share Posted May 15, 2005 No, will not last long term, Quote Link to comment Share on other sites More sharing options...
deeveus Posted June 21, 2005 Author Report Share Posted June 21, 2005 Just to bring up this topic again. I have setup a cold marine to house native NZ fishes. I have purchased some crayfish and paua from this guy on trademe. Just a quick question, what temp is NZ water down the bottom of the south island? Anyone know? I will post pics of the setup once I have put the crays and the paua in. Quote Link to comment Share on other sites More sharing options...
reef Posted June 21, 2005 Report Share Posted June 21, 2005 I would do you homework first before you add anything. If you dont know the temp then you have not done the research.\ Not trying to be smart, but i just hate seeing animals die for no good reason. Quote Link to comment Share on other sites More sharing options...
Pies Posted June 21, 2005 Report Share Posted June 21, 2005 I'd be looking at keeping the tank no warmer than 14 degrees, down to as low as 8. You will need a chiller. Pie Quote Link to comment Share on other sites More sharing options...
Faran Posted June 21, 2005 Report Share Posted June 21, 2005 I usually drop crays in the water when it gets to a rolling boil. They turn red and serve up nicely with garlic butter.... Just kidding, the "natural NZ ocean" tank is something that I'm quite keen on. Let us know how it goes! Quote Link to comment Share on other sites More sharing options...
deeveus Posted June 21, 2005 Author Report Share Posted June 21, 2005 Sorry reef, but you can't of read my post correctly. I specifically asked for lower south island water temperatures so that I could gain information of weather or not I could house north island fishes alongside. I know the exact water parameters to house crays and paua as I have done my research. I am also going to put in other lower south island fish species with regard to the species I know you can have. I will however reasearch and see if I can house the ones I am unsure about. Quote Link to comment Share on other sites More sharing options...
deeveus Posted June 21, 2005 Author Report Share Posted June 21, 2005 I'd be looking at keeping the tank no warmer than 14 degrees, down to as low as 8. You will need a chiller. Pie Hey pies. The person I purchased them off says that they can survive in temperatures up to 25 degrees seing as that is paua's spawning temp, as for a cold Dunedin's house, temp shouldn't be a problem. Ofcourse it will be monitored but I know people who keep cold marine here in dunedin and a chiller has never been needed. Quote Link to comment Share on other sites More sharing options...
Pies Posted June 21, 2005 Report Share Posted June 21, 2005 25 degrees is the same temprature I keep my reef to keep corals, its FAR to hot and very un-natural. I don't think there would be a place in NZ that ever get warmer than 22 degrees. I am sure than can survive short periods at this temprature, but not sustainable. Keeping them to warm will kill them, this is a fact, and the reason why its so hard to keep rockpool tanks. As for room temprature, the World Health Organisation suggests that your house should never be cooler than 18 degree's, its unhealthy and can lead to all sorts of respitory illness's including athsma, so i'd be surprised if you place is that cold all of the time. Pie Quote Link to comment Share on other sites More sharing options...
deeveus Posted June 21, 2005 Author Report Share Posted June 21, 2005 No, it would not be 18 all the time. During the day when no one is here, it would be quite cold - old house - no insulation and very drafty. This should balance the temp. Quote Link to comment Share on other sites More sharing options...
klaymann Posted June 21, 2005 Report Share Posted June 21, 2005 As far as I know the temp range for Crays should be between 11 and 18 degrees ... the Cray tanks I looked after for clients all had chillers except one 6 footer in an old villa .. at 23 degrees they don't far well and often got fungus or died .. color wasnt the best either.. but thats only what I've seen.. Quote Link to comment Share on other sites More sharing options...
klaymann Posted June 21, 2005 Report Share Posted June 21, 2005 Deeveus .. I would be careful with introducing fish to your cray tank .. have seen fish and crays get on well for over a year but suddenly cray turns into " demon cray" and kills all the other inhabitants ( evil or just mature sexual aggression) ?? Crays do hunt at night .. you can hear them stompin' around in the dark and lo an' behold in the morning one fish is sushi.. :-? Quote Link to comment Share on other sites More sharing options...
deeveus Posted June 21, 2005 Author Report Share Posted June 21, 2005 Cheers for the input. Learned by myself further, a detailed email from the provider of my crayfish. This is how he operates his holding systems and breeds in these environments: Paua Holding instructions Aquatic Enterprises ltd Ó. Introduction. Paua are oceanic animals. The marine environment they live in is rich in oxygen, low in ammonia, nitrite, CO2 and suspended solids. I use the listed parameters below and they are well within the survival range. Parameters outside of these ranges may stress the guys out without showing signs of stress right away. Water Quality Parameters Parameter Range Temperature 9 -19deg c pH >7.9 and <8.4 Salinity Between 32 and 36 mg/L Oxygen 80% saturation Nitrite (NO2) <0.1mg/L Nitrate (NO3) <23mg/L Ammonia (NH3) < 0.5 mg/L Temperature The temperature these guys live in is close to 9C in winter and a high of 19 in the summer. Salinity Ensure you slat water source is not close to any fresh water run off if you are using sea water. Try and collect the salt water from clean source. Fresh water can sit on the top of sea water if it has been raining heavily so deeper is better. Try and avoid sediment. Salts can be purchased from pool shops if you intend making you own. The measurement ppt is the same as mg/L and means parts per thousand. Knowing this can help in your calculations of water salinity levels. The best tool for measuring this is a refractometer (makes the job easy). If mixing your own salt water with town supply you will need to make sure you either use rain water or get rid of the chlorine component. Chlorine can be removed by aerating or using the chemical sodium thiosulphate. pH, Nitrite, ammonia pH, nitrite and ammonia test kits are available from most pet stores. Ammonia and Nitrite can be a lethal combination if they occur together. If your tank is new your water should be changed regularly in the first couple of weeks. Oxygen Oxygen is very important. Equipment for this expensive so as a rule of thumb you need to make sure you have plenty of water movement. When water becomes warm the fish need more Oxygen because there will be less in water. Dissolved Organic matter The water should be changed before it becomes brown and foamy this is a sign water quality deterioration. Overfeeding will help cause this. Feeding Paua farming in New Zealand currently relies on artificial food imported from Australia or natural seaweed diets. Keep the food refrigerated to protect the vitamins. Generally the feed should be presented in the evening so as nutrient components don’t leach out of the food. As a guide when feeding, their should be little food left over in the morning. Around 2% body weight per day is the recommended dose. Two or three pellets to start with should be fine. Clean old pellets out every two to three days to maintain water quality. Substrate Paua are cryptic and prefer to have hiding places. Clean rocks can be placed in the tank so as the animals have a place to hide. Try and create some water movement around the tank so that there are no dead spots for the water to stagnate. Large flat rocks are good for Paua. Sometimes they are a little to good at hiding. Handling Paua Paua have no blood clotting mechanism so can bleed to death if cut. When handling paua use a non serrated butter knife. Alternatively if you are fast enough you will not need a knife. Slide the paua rather then pulling at it. You will get better with practice. Final note The above guide is designed to aid the aquarist in caring for their pet. If all the water parameters for this pet are met there is no reason the pet shouldn’t live for thirty years or more. As a general note if in doubt change the water. If you have all the tools for measuring parameters there is less doubt. Be good to your pets and good luck. Quote Link to comment Share on other sites More sharing options...
deeveus Posted June 21, 2005 Author Report Share Posted June 21, 2005 For cray's: Crayfish Holding instructions Aquatic Enterprises ltd Ó. Introduction. Crayfish are oceanic animals. The marine environment they live in is rich in oxygen, low in ammonia, nitrite, CO2 and suspended solids. I use these parameters and they are well within the survival range. Parameters outside of these ranges will stress the guys out and they may not show signs of stress right away. Water Quality Parameters Parameter Range Temperature >9 <19 pH >7.9 and <8.4 Salinity Between 32 and 36 mg/L Oxygen 80% saturation Nitrite (NO2) <0.1mg/L Nitrate (NO3) <23mg/L Ammonia (NH3) < 0.5 mg/L Temperature The temperature these guys live in is close to 9C in winter and a high of 19 in the summer. This animal is extremely robust if you have a chiller. If you do not have a chiller unit keep tank out of direct sunlight and away from heaters and fires. They are not like tropical fish and can be sensitive to temperature spikes. Gradual changes are better. Temperature changes in the ocean are gradual. Salinity Ensure you slat water source is not close to any fresh water run off if you are using sea water. Try and collect the salt water from clean source. Fresh water can sit on the top of sea water if it has been raining heavily so deeper is better. Try and avoid sediment. Salts can be purchased from pool shops if you intend making you own. The measurement ppt is the same as mg/L and means parts per thousand. Knowing this can help in your calculations of water salinity levels. The best tool for measuring this is a refractometer (makes the job easy). If mixing your own salt water with town supply you will need to make sure you either use rain water or get rid of the chlorine component. Chlorine can be removed by aerating or using chemical sodium thiosulphate. pH, Nitrite, ammonia pH, nitrite and ammonia test kits are available from most pet stores. Ammonia and Nitrite can be a lethal combination if they occur together. If your tank is new your water should be changed regularly in the first couple of weeks. Oxygen Oxygen is very important. Equipment for this expensive so as a rule of thumb you need to make sure you have plenty of water movement. When water becomes warm the fish need more Oxygen because there will be less in water. Dissolved Organic matter The water should be changed before it becomes brown and foamy this is a sign water quality deterioration. Overfeeding will help cause this. Feeding Crayfish farming in new Zealand currently relies on fresh mussels for the diet. Mussels are considered a complete diet for crayfish though they may vary in condition seasonally. Some prawn pellets are used successfully in their culture but should be supplemented with mussels at least once per week. Oily fish are also a good protein source. Substrate Crayfish are cryptic and prefer to have hiding places. Clean rocks can be placed in the tank so as the animals have a place to hide. Try and create some water movement around the tank so that there are no dead spots for the water to stagnate. Tank size Your tank size is not as important as your water quality monitoring. Literature values suggest that 0.15kg/L can be held. The small animals are about 25g (0.025 kg). Obviously it is easier to maintain water quality parameters in a larger tank. I would suggest a minimum tank set up of 20 litres and an under gravel system and an airlift pump. Have plenty of Air if you have no protein skimmer. Final note The above guide is designed to aid the aquarist in caring for their pet. If all the water parameters for this pet are met there is no reason the pet shouldn’t live for thirty years or more. As a general note if in doubt change the water. If you have all the tools for measuring parameters there is less doubt. Be good to your pets and good luck. Quote Link to comment Share on other sites More sharing options...
Ira Posted June 21, 2005 Report Share Posted June 21, 2005 My understanding was that mg/L was roughly equal to parts per MILLION. If it was PPT then his less than 23 mg/l of nitrates would be 23,000 PPM. Quote Link to comment Share on other sites More sharing options...
Chikan Posted June 21, 2005 Report Share Posted June 21, 2005 I work in a aquarium where we keep a large number of red, albino and packhorse crayfish. In my expeirience in keeping crayfish you need a few things Large volume of water Monitor temperature closely Monitor salinity closely Regular water changes up to twice a week with preferably a constant top up source providing change over of the water ( keeps the temp down). You need to watch crayfish as they are canniballistic and will fight and kill each other. Would recommend that you keep only one. They need hiding places to be happy. As for keeping cod probably a bit ambitious without a good and reliable sw source for constant water changes. The problem with both of these species is that they both produce a lot of ammonia and will be reasonably sensitve to water quality. Another thing that i would wonder about buying aquacultured crays is the quality of them. Aquacultured species that i have deal with in the past are usually not as good as wild catch and usually develop problem down the line due to there rearing and environment they come from. Not always but is worth considering alternatives. Good luck with the tank though i have two cold water marine tanks and both go good. The secret is water quality and frequent water changes with filtered sw. Quote Link to comment Share on other sites More sharing options...
deeveus Posted June 21, 2005 Author Report Share Posted June 21, 2005 Hey Chikan. Thanks for the advice, I am to do a 20litre water change per week and my tank is 130litres and with a trickle filter and protein skimmer. I was a little unsure when he said that 20 litres would be ok. P.S Have you got any pics and recommendations of communities? Quote Link to comment Share on other sites More sharing options...
klaymann Posted June 22, 2005 Report Share Posted June 22, 2005 Interesting that he mentions u/g filters ... being a supporter of these for basic salt water tanks ( read not reef ) ... I won't use them in a cray system due to nitrates etc ... cant keep seaweeds to take care of these as I have found that crays shred them ( food sup or boredom?) ... :-? Quote Link to comment Share on other sites More sharing options...
klaymann Posted June 22, 2005 Report Share Posted June 22, 2005 Chikan .. do you use micron filters for the NSW ? . Quote Link to comment Share on other sites More sharing options...
Chikan Posted June 23, 2005 Report Share Posted June 23, 2005 I use a 5 mircon pool filter with a bulkhead for flow adjustment. I'm lucky and use sw that has been filtered through a sand pre filter at work as well. My advice is pick a good natural source for collecting sw like a channel and get it at slack of high tide. Also a reverse osmosis and uv filter could be a bonus but not always necessary. I wouldn't use a undergravel filter too many maintanance issues like nitrate problems and organic build up. Trickle filters are the best or a good large canister filter. Deevus cold marine tanks are awesome and quite rewarding. I have found that anemonies, crab, starfish, cucumbers, sea squirts are fasinating communities to watch, keep and feed. I get just as much enjoyment when watchin them as my trop reef tank and they don't cost anything. A 20 to 25% water weekly should be cool but you should have any problems doing them for temp reasons down there so just monitor your nitrite levels and adjust your water changes depending on these. Quote Link to comment Share on other sites More sharing options...
Chikan Posted June 23, 2005 Report Share Posted June 23, 2005 Ps I would think that the crays are messing which the seaweed for play when diving it is know that you never find crays in holes that have old or broken seaweed outside them. They don't use it in there diet. I 'm creating a page on myspace at the moment with profiles and pics of my tanks including my newest tank which is housing a baby octopus. Will post link soon as just been busy at the mo. Quote Link to comment Share on other sites More sharing options...
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