There are a few points that clearing up.
Firstly, the terms ‘tortoise’, ‘turtle’ and ‘terrapin’ are not part of scientific classification. They are common names. Beginning of the 1970s there was a push to get the terms to align more with the scientific classifications and therefore be more meaningful. Scientific classification distinguishs between those adapted to a completely terrestrial existence and those capable of living partly or wholly in water. Terrestrial forms have solid, stubbed feet with short, thick digits bearing broad flat nails and lacking any webbing between them. Partially aquatic forms have less robust limbs, with relatively much longer digits, each bearing a claw and with substantial webbing between them. In totally aquatic species, the upper and lower limbs are relatively short while the digits are elongated and interspersed by fleshy tissue to form a flipper.
Initially, Australian freshwater chelonians were called tortoises. In particular, Chelonia longicollis was known as the Common Snake-necked Tortoise. (That name is still used today by some.) Based on the fact that all land chelonians worldwide were called tortoises and that all totally aquatic chelonians worldwide were called turtles, it was deemed appropriate that Australia’s freshwater chelonians, which are a semi-aquatic, bar one fully aquatic, should be referred to as
turtles.
Dragon-nut is correct about the origins of terrapin. It was originally applied to a genus of North America brackish water turtles and has been picked up by the pet trade in the UK and is generally used to apply to some or all semi-aquatic turtles. This usage has fed back to the USA where the term now has a much broader use that originally. We would not use the term at all under our system of common names.
Killimike did well to explain most of the waste issue. Turtles take in their food and break down what they can to use for growth and energy. What they cannot breakdown comes out as solid waste = poo. What is used for growth remains in the body. What is used for energy is broken down completely and released as soluble wastes – ammonia, urea and dissolved minerals such as phosphates. Ammonia is extremely toxic and if allowed to build up, would soon get to the level where the health of the animals living in the tank was affected. It could ultimately kill them.
Filtration is of two or three types.
Physical Filtration removes undissolved particles and debris suspended in the water. So bit of undigested food stirred up by the turtles movement would be removed in this manner to keep the water clear.
Biological Filtration does not actually physically remove anything from the water. What is does do is to use bacteria and oxygen to change the extremely toxic ammonia into far less toxic nitrites and then to change these into the fairly low toxicity nitrates. Some filters also have
Chemical Filtration where by certain dissolved minerals can be removed. Things like activated carbon, zeolite, and the example given earlier for phosphates. Note: Simple addition of zeolite to the bottom of the tank can be very useful (depending upon your filtration set up and method of cleaning). Activated carbon is effective for only a very limited time and needs to be replaced or re-activated (dried and heated). Very few freshwater tanks use continuous chemical filtration – it is too much work for too little gain.
UVC sterilisation can be incorporated with filtration. Exposure to strong UVC radiation kills anything biological in the water. This will help slow the colonisation of algae but will not stop it happening and progressing once it gets started.
Plants use ammonia, urea and nitrates as their main source of nutrients plus the other minerals like phosphates. The other thing plants need is energy, which they get from light. The rate of growth of plants will be limited by the level of availability of either nutrients or light. In the limited volume of a tank, the nutrient levels tend to be higher than in nature, so providing strong light such as sunlight allows very rapid growth. If nutrients levels were close to zero, it would not matter how much light was provided, growth would be very limited
The turtle’s light should not be cut back. It should be getting 8 to 12 hours each day. The suggestion by
Killimike to user a timer is excellent advice and I strongly your friend do so. The real problem is how to reduce the nutrients present in the water, bearing in mind they are being continuously produced.
Do not over feed the turtle. Give it just what it needs and no more. Extra food means extra nutrients for plant growth.
Change a significant volume of the water on a regular basis. A water change of 50% will remove half of the nutrients. Scheme water does have minerals in it but not nitrogenous minerals. The ideal would be rainwater if you can get it but it is not essential.
Have animals that eat algae and grow as a result. The poo these animals produce is primarily cellulose that was not digested and this does not add to the nutrient load. A percentage of what they eat will be converted to energy and will therefore reconvert some plant material into nutrient load. Crayfish large enough for the tortoise not to eat are a possibility. The cheap algae eaters tend to grow fast – so they’d be good. Ramshorn snails will do a good job if you don’t mind several dozen or more. There are some beautiful colours available, such as pink or blue. I have never tried Apple Snails but that suggestion might be worthwhile. Do NOT use pond snails – the ones with the conical shell – as they will eat water plants. Ramshorn will graze algae off of water plants without doing much damage.
Have plants in your tank that the turtle will not eat and will grow rapidly enough to remove the nutrients and out grow the algae. Ribbon Weed (Vallis or Vallisneria) is probably the best choice here. Turtles will eat it in small quantities but its rapid growth, especially under high nutrient loads, will compensate. Simply harvest it on a regular basis and throw in the compost. You can also grow some pants hydroponically with only their roots in the water, rooted into the gravel e.g. Spathiphyllum, Philodendrons, Devil’s Ivy, Dwarf Papyrus, Dwarf Bulrushes etc. All will help to assist in removing nutrients from the water.
Vallis plus algae eaters plus snails would be my preference.
Blue
What a great post.
.......solar 17 (Baden)
There are a few points that clearing up.
Firstly, the terms ‘tortoise’, ‘turtle’ and ‘terrapin’ are not part of scientific classification. They are common names. Beginning of the 1970s there was a push to get the terms to align more with the scientific classifications and therefore be more meaningful. Scientific classification distinguishs between those adapted to a completely terrestrial existence and those capable of living partly or wholly in water. Terrestrial forms have solid, stubbed feet with short, thick digits bearing broad flat nails and lacking any webbing between them. Partially aquatic forms have less robust limbs, with relatively much longer digits, each bearing a claw and with substantial webbing between them. In totally aquatic species, the upper and lower limbs are relatively short while the digits are elongated and interspersed by fleshy tissue to form a flipper.
Initially, Australian freshwater chelonians were called tortoises. In particular, Chelonia longicollis was known as the Common Snake-necked Tortoise. (That name is still used today by some.) Based on the fact that all land chelonians worldwide were called tortoises and that all totally aquatic chelonians worldwide were called turtles, it was deemed appropriate that Australia’s freshwater chelonians, which are a semi-aquatic, bar one fully aquatic, should be referred to as turtles.
Dragon-nut is correct about the origins of terrapin. It was originally applied to a genus of North America brackish water turtles and has been picked up by the pet trade in the UK and is generally used to apply to some or all semi-aquatic turtles. This usage has fed back to the USA where the term now has a much broader use that originally. We would not use the term at all under our system of common names.
Killimike did well to explain most of the waste issue. Turtles take in their food and break down what they can to use for growth and energy. What they cannot breakdown comes out as solid waste = poo. What is used for growth remains in the body. What is used for energy is broken down completely and released as soluble wastes – ammonia, urea and dissolved minerals such as phosphates. Ammonia is extremely toxic and if allowed to build up, would soon get to the level where the health of the animals living in the tank was affected. It could ultimately kill them.
Filtration is of two or three types. Physical Filtration removes undissolved particles and debris suspended in the water. So bit of undigested food stirred up by the turtles movement would be removed in this manner to keep the water clear. Biological Filtration does not actually physically remove anything from the water. What is does do is to use bacteria and oxygen to change the extremely toxic ammonia into far less toxic nitrites and then to change these into the fairly low toxicity nitrates. Some filters also have Chemical Filtration where by certain dissolved minerals can be removed. Things like activated carbon, zeolite, and the example given earlier for phosphates. Note: Simple addition of zeolite to the bottom of the tank can be very useful (depending upon your filtration set up and method of cleaning). Activated carbon is effective for only a very limited time and needs to be replaced or re-activated (dried and heated). Very few freshwater tanks use continuous chemical filtration – it is too much work for too little gain.
UVC sterilisation can be incorporated with filtration. Exposure to strong UVC radiation kills anything biological in the water. This will help slow the colonisation of algae but will not stop it happening and progressing once it gets started.
Plants use ammonia, urea and nitrates as their main source of nutrients plus the other minerals like phosphates. The other thing plants need is energy, which they get from light. The rate of growth of plants will be limited by the level of availability of either nutrients or light. In the limited volume of a tank, the nutrient levels tend to be higher than in nature, so providing strong light such as sunlight allows very rapid growth. If nutrients levels were close to zero, it would not matter how much light was provided, growth would be very limited
The turtle’s light should not be cut back. It should be getting 8 to 12 hours each day. The suggestion by Killimike to user a timer is excellent advice and I strongly your friend do so. The real problem is how to reduce the nutrients present in the water, bearing in mind they are being continuously produced.
Do not over feed the turtle. Give it just what it needs and no more. Extra food means extra nutrients for plant growth.
Change a significant volume of the water on a regular basis. A water change of 50% will remove half of the nutrients. Scheme water does have minerals in it but not nitrogenous minerals. The ideal would be rainwater if you can get it but it is not essential.
Have animals that eat algae and grow as a result. The poo these animals produce is primarily cellulose that was not digested and this does not add to the nutrient load. A percentage of what they eat will be converted to energy and will therefore reconvert some plant material into nutrient load. Crayfish large enough for the tortoise not to eat are a possibility. The cheap algae eaters tend to grow fast – so they’d be good. Ramshorn snails will do a good job if you don’t mind several dozen or more. There are some beautiful colours available, such as pink or blue. I have never tried Apple Snails but that suggestion might be worthwhile. Do NOT use pond snails – the ones with the conical shell – as they will eat water plants. Ramshorn will graze algae off of water plants without doing much damage.
Have plants in your tank that the turtle will not eat and will grow rapidly enough to remove the nutrients and out grow the algae. Ribbon Weed (Vallis or Vallisneria) is probably the best choice here. Turtles will eat it in small quantities but its rapid growth, especially under high nutrient loads, will compensate. Simply harvest it on a regular basis and throw in the compost. You can also grow some pants hydroponically with only their roots in the water, rooted into the gravel e.g. Spathiphyllum, Philodendrons, Devil’s Ivy, Dwarf Papyrus, Dwarf Bulrushes etc. All will help to assist in removing nutrients from the water.
Vallis plus algae eaters plus snails would be my preference.
Blue
What a great post.
.......solar 17 (Baden)
