Crayfish holding instructions
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 your 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 your 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. Substrate covering the bottom should be gravel with a diameter of about 3-4 mm. Fine sand is not suitable as it packs in and tends 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.
How much to spend on your aquarium
The most basic aquarium set ups should have at least an under water gravel filter with an air lift pump. These can be purchase from most pet stores. Under water gravel filters are great as these turn the entire gravel substrate in a biological filter mat. This creates large water conditioning capacity as well as makes a practical use for your substrate. Gravel filters should be accompanied with an airlift pump to suck water through the gravel.
Protein skimmers and chiller units can be added to the tank to reduce the time spent monitoring the tanks. Alternatively rapid filtration using a motor driven internal filter with a centrifugal pump are often used for marine aquariums. These get clogged quickly in high protein environments.
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.
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 your 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 your 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. Substrate covering the bottom should be gravel with a diameter of about 3-4 mm. Fine sand is not suitable as it packs in and tends 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.
How much to spend on your aquarium
The most basic aquarium set ups should have at least an under water gravel filter with an air lift pump. These can be purchase from most pet stores. Under water gravel filters are great as these turn the entire gravel substrate in a biological filter mat. This creates large water conditioning capacity as well as makes a practical use for your substrate. Gravel filters should be accompanied with an airlift pump to suck water through the gravel.
Protein skimmers and chiller units can be added to the tank to reduce the time spent monitoring the tanks. Alternatively rapid filtration using a motor driven internal filter with a centrifugal pump are often used for marine aquariums. These get clogged quickly in high protein environments.
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.
posted by Pewana at 3:26 PM
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