Water Quality for Aquatic Caudates

by Jennifer Macke

Paramesotriton hongkongensis

Aquatic animals need healthy water that stays healthy long-term. This is an important, but often overlooked, aspect of keeping aquatic amphibians. Just because your tank water looks crystal clear does not mean it is healthy!

The following are the basics of water quality assembled into 10 points. These same rules apply to keeping fish, and you can find similar information in many fish-keeping books. If you follow these suggestions carefully, it will help your aquatic caudates live to a ripe old age.

1. Understand the nitrogen cycle.

Animal wastes and uneaten food produce toxic waste products (ammonia and nitrite). Beneficial bacteria in the tank convert these toxins to a less-toxic form (nitrate). This process is called "biofiltration" because these bacteria filter out the toxic waste products from the water. Here are some links that explain the process in more detail:

2. You cannot have a healthy tank without bacteria (so donít try).

A well-established tank (up and running >2 months) has a huge population of beneficial bacteria that detoxify ammonia and nitrite. If you think that bacteria are nasty or evil, think again. Most bacteria in this world do us more good than harm, and this is especially true in an aquarium. The bacteria in your tank are essential to long-term water quality. The service performed by these bacteria is called "biofiltration". There is no mechanical or chemical filtration process that can completely substitute for biofiltration. The process of getting the beneficial bacteria established in your tank is called "cycling".

A very clean tank Ė or a new tank Ė can be dangerous. Why? Because it is not yet cycled - it does not contain the beneficial bacteria that break down wastes. Ammonia and nitrite can build up and poison the animals. Ammonia and nitrite are colorless and clear, so you won't necessarily see the problem.

3. If possible, cycle a new tank before adding newts.

It takes several weeks for good bacteria to become established in a new tank. The process of establishing these bacteria is called "cycling". During this period, the tank may reach toxic levels of ammonia and nitrite. It is essential to have few or no animals in the tank during this period, and to test regularly for ammonia and nitrite. For more detail, please read the following article:

4. Protect your tank slime.

Where do beneficial bacteria grow? On any wet surface in your tank: on the glass, the gravel, the rocks, the aquarium ornaments, the filter. You may notice that these surfaces are slimy. This slime is your biofilter. Here are some simple things you can do to take care of it:

  • If you must use an antibiotic treatment for a sick newt, do the treatment in a separate quarantine tank so you donít kill the good bacteria in your main tank.
  • If you want to clean your tank, donít clean all the ornaments and the filter all at once. If you do, youíve just killed most of your biofilter and the tank may have to start the cycling process all over again.
  • Choose tank decorations that have rough surfaces where more bacteria can colonize, such as natural rock and terracotta.
  • Choose a color of gravel that wonít show the algae, and you will never have to scrub it. (However, you will still have to remove debris diligently.)
  • Understand that algae, in moderation, is not bad. Most algae have all the same benefits of live plants Ė oxygen production and nutrient consumption. If you get excessive algae, particularly the ugly kinds, take steps to reduce it. But never take the whole tank apart and scrub everything off unless absolutely necessary.
  • If you are starting a new tank, use some pieces of filter media or gravel from the older tank to help establish the bacteria in the new tank.

5. Do water changes and tests regularly.

Even in a healthy, well-established tank, nutrients build up in the water. The only way to remove these is to remove a portion of the water in the tank and replace it with fresh water. A typical water change removes about 20% of the tank water. During the "cycling" period, this may need to be done every few days if you already have animals in the tank. You should test the ammonia and nitrite levels just before doing a water change. Once the tank has been established for several months, it can be maintained with a partial water change (10-20%) every 1-2 weeks.

6. Do not keep too many animals in one tank.

Overcrowding puts the lives of all your animals in danger by degrading water quality and putting the animals at greater risk of illness. Even when a tank doesnít look crowded, it may have more animals than the carrying capacity of the water allows. As an example, a 10-gallon tank can support about 12 inches of animal (three 4-inch newts, for example), and a 15-20 gallon tank can easily support about 16 inches of animal. These figures assume that the tank is at least 2/3rds full of water. Any fish or other animals in the tank also count toward the total. Any animals beyond this could result in overcrowding.

Don't take what you see in pet stores as a good example! Pet stores often have overcrowded tanks. They are able to get away with this because (1) the situation is often temporary - crowding decreases as the animals are sold, and (2) they are able to do much more massive water changes than what you would want to do at home.

7. Do not overfeed.

Feed only as much as the newts will eat in one sitting. Use a turkey baster to remove uneaten food right away. Well-established adult newts do not need to eat very often. As long as they donít look skinny, twice a week is perfectly OK.

8. Remove debris and clean the filter frequently.

Filters do not make dirt go away. They only concentrate the dirt in one place to make removal easier. Even if you canít see it, the dirt in the filter is still in the aquarium, producing waste products.

9. Keep the water well oxygenated.

Beneficial bacteria thrive on oxygen, and die without it. Oxygen discourages fungi. Oxygen in the water is important for amphibians, since many of them breath through their skin to some extent. An airstone or spray bar of some kind will do the trick.

10. Use a water conditioner that gets rid of chloramine.

About half of the waterworks in the U.S. now use chloramine, not chlorine. Letting your tap water sit out overnight will NOT get rid of chloramine, you must use a treatment product. After treating, it is still a good idea to let the water sit overnight also, to allow dissolved gasses to dissipate, and for the temperature to equilibrate to match your tank. How do you know for sure if your waterworks is using chloramine? Do an ammonia test on your tapwater. If you have ammonia there, it means your waterworks uses chloramine. Even if your waterworks doesnít use chloramine today, it may switch over (and they might not tell you when they do!). Get used to the idea of chloramine, and use an appropriate product to get rid of it.

You may be surprised to learn that aging water overnight does not entirely get rid of chlorine either. Depending on the temperature and the size/shape of the container, it can take over a week for chlorine to dissipate from tap water. Again, even if you have just chlorine, you probably need to use an appropriate water conditioner to treat the water before use.

Additional Resources

  • Water Quality FAQ
    An additional page of water quality information on this site.
  • A Dozen Don'ts
    A nice simple compilation of things you shouldn't do when maintaining an aquarium. Written for goldfish, but equally relevant to amphibians.

© 2001 Jennifer Macke. Revised December 2001. Revised January 2006.


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