How to Take Care of Fish | Aquarium Care Basics | Tips


Basic fish Aquarium

For fish, water is the air they breathe, the house they live in, their source of all things necessary for their life.  Fish are not able to protect themselves from their environment to the extent that land animals can.  They don’t have fur nor the ability to regulate their body temperature.  Living in water puts them in fish aquarium intimate contact with toxins and bacteria that do not have the same effect on land animals because air and our dry skin provides a natural barrier.



Therefore, ensuring that the fish Aquarium has high-quality water to live in is essential.  It is so important that the majority of this document deals with maintaining the quality of the water and environment the fish live in.  The needs of fresh and saltwater fishes are slightly different, but there are also some common needs.



Water must be free of toxins.  Toxins can be present in the water supply and they also are produced by the fishes themselves, as waste products of their metabolism.  Toxins present in the water supply include chlorine and chloramine that are added to prevent bacterial growth in drinking water, copper and other metals which may come from water pipes and other chemicals that may be present in groundwater.


The toxins produced by the fishes are primarily ammonia.  Chlorine, chloramine, and ammonia can be measured in a tank using commercial test kits.
Toxins in water are controlled by pre-treating water and by filtration of the water in the tank.


  • Water may be pre-treated by treating it chemically with sodium thiosulfate (1 ml of 1% thiosulfate/10 gallons of water) or an equivalent product, to remove chlorine.


  • Some chemical products available in pet stores will remove both chlorine and chloramine.


  • Chlorine may also be removed by exposing the water to light for 24 hours, or by aerating it.


  • Activated carbon will remove both chlorine and chloramine, as well as some other toxins.


  • If there is heavy metal contamination of the water, it will probably be necessary to find another source of water.




There are three separate components of filtration:  mechanical, chemical and biological filtration.


  • Mechanical filtration refers to the removal of solid particles in the water.  Substances such as floss, gravel or a foam filter cartridge serve as mechanical filters.


  • Chemical filtration is accomplished using activated carbon, ammonia absorbents or water softeners.


  • Biological filtration is provided by normal denitrifying water bacteria (Nitrosomonas and Nitrobacter spp) which break down ammonia into nitrites and nitrates.  Ammonia and nitrites are toxic, while nitrates are non-toxic to fishes.  Water bacteria play an essential role in maintaining water quality.

There are a number of filtration systems that accomplish these tasks.


  • Corner Filters are a very simple system that utilizes an air supply to create a slight vacuum to draw water into the filter.  There, floss and activated carbon help to filter the water.  The filter also provides a substrate for denitrifying bacteria to grow.  The air supply, also, provides aeration for the water.


  •   These filters can only filter a limited amount of water and support the limited number of fish in a tank.  The filter contents need to be changed when they become soiled.  It is recommended to used them in conjunction with aquarium gravel to provide an extra substrate for denitrifying bacteria to grow on.


  • Outside Power Filters use an electrical pump to draw large amounts of water into the filter and pass it over filter floss and carbon to efficiently filter the water.  They also provide excellent aeration for the water.  They can support a large number of fish aquariums than other methods.  The filter contents need to be changed when they become soiled.  This filter does not provide as efficient of biological filtration, and gravel is recommended for the bottom of the aquarium to provide a substrate for denitrifying bacteria to grow on.


  • Undergravel Filters use an air supply to create a vacuum that draws water through the gravel.  The gravel provides both mechanical and biological filtration, but not chemical.  These systems are extremely low maintenance but do not support as may fish as other systems.  This system should be supplemented with periodic “vacuuming” of the gravel with a siphon or pump to remove trapped debris.


  • Foam Filters are attached to an air supply and placed into the tank.  They provide excellent aeration and a substrate for the growth of denitrifying bacteria to provide biological filtration.  They also provide some mechanical filtration by trapping debris.  These filters are usually used as adjuncts to other systems or the sole filtration for small tanks with few fishes.


  • Canister Filters are a filtration system that is placed in-line in a pump.  Like outside filters, they can process a large amount of water and provide all three types of filtration.  However, attention must be paid to regular changing of the filter substrate, as it will cease to function when overloaded.


  • Flow-Through Systems have a continuous water supply and drain.  These systems can support large numbers of fish Aquarium have a water supply conditioning system and consume large amounts of water.  These are not recommended for most pet fish needs.



Filter Substrates can have an effect on water quality:


  • Dolomite gravel can elevate the pH of the water.  This can be useful in areas where water hardness is low.


  • Zeolites can help buffer water and maintain it in an ideal range of 7.4.


  • Peat moss can be used for softening water and reducing pH.  It may stimulate ovulation in breeding fish Aquarium.


Fish Aquarium Temperature

Temperature is a very important part of a fish’s environment. fish Aquarium Improper temperatures can adversely affect a fish’s health.  High temperatures reduce the amount of oxygen in the water, reducing tank capacity.  It is important to consult an aquarium book to determine the temperature range of the fish you are keeping.  In general, goldfish and native fishes prefer cooler temperatures:  no more than 75 F and they may tolerate temperatures just above freezing.


Tropical fish prefer temperatures over 75 F and 80-85 F are preferable for many species. Heaters can be used to provide temperatures above room temperature.  It may be necessary to keep fish Aquarium in a cold room or area if lower temperatures are needed.  Temperature is monitored using any of a number of available thermometers.


The pH of the water is a measure of the acidity of the water in a fish aquarium.  For freshwater fish, this should be in the range of 6.8-7.2.  Saltwater fish require a higher pH of 7.8-8.3.  Higher pH can enhance the formation of ammonia in the water, while low pH can adversely affect the function of the fishes’ gills and can be detrimental to the growth of denitrifying bacteria.  Water pH can be adjusted with commercially available buffers.  Water pH can be measured in a tank using commercial test kits.



Like all animals, oxygen is essential to the survival of fish.  Oxygen is absorbed in the water-air interface.  Providing turbulence to the water through the use of a pump or an air supply can increase the oxygenation of the water.


Cooler water can hold more oxygen than warmer water can.  Excessive oxygenation can be detrimental to some animals that are accustomed to living in stagnant water, or if the water becomes hyper oxygenated through the use of a water pump.


This is not likely to be a problem for most aquarium fishes.  Oxygen concentration can be measured in a tank using commercial test kits.  It should be between 5 and 7 ppm.

Specific Gravity

The specific gravity of water is a measure of the ionic strength of water; i.e. the number of other chemicals dissolved in it.  Pure water has a specific gravity of 1.0.  The addition of salt in levels of 0.1-0.3% to freshwater may reduce the amount of energy needed for freshwater fish and reduce stress.


This may be used when they are ill or otherwise stressed, such as during shipping.

Saltwater fish must have a specific gravity in the range of 1.017 to 1.023.  For saltwater fish, the lower end of the range can be used to aid the fish when stressed.


However, the high end of the range should be used under normal circumstances as it may combat some parasitic infections.
Specific gravity can be measured in a tank using commercial test kits or a refractometer.

Hardness and Alkalinity

The hardness of water refers to the amount of calcium and magnesium dissolved in the water.  The alkalinity of water refers to the number of other anions, such as carbonates, bicarbonates, hydroxides, silicates, and borates, that are dissolved in the water.  Generally, these two measures are very close.


They can be measured using commercial test kits and are expressed in parts per million (ppm).  Soft water has a hardness/alkalinity of less than 100 ppm.  Hard water has a hardness/alkalinity between 100 to greater than 200 ppm.  Water needs to have a certain amount of hardness to provide an optimal environment for the fish.  It helps to buffer pH changes.  If using soft water it may be necessary to add commercially available pH buffers, which is essentially extra “hardness” for the water.




Decorations such as rocks, wood, plants, and other plastic items can be functional, in providing hiding places for fish.  When using natural products such as rocks or wood, it is a good idea to test them with some extra fish before adding to the main tank.


Rocks may leech out heavy metals that can be toxic to fish.  Wood and natural plants may carry harmful bacteria or disease vectors such as snails that may endanger the tank. fish aquarium  Wood may be dried first to decontaminate it.  Plants can be submitted to an alum or potassium permanganate (3 ppm) bath for several minutes to osmotically damage any parasites that are being carried.


fish Aquarium Carrying Capacity

The carrying capacity of a  fish Aquarium is the number of fish it can hold.  This is determined by many things such as filtration system, type of fish, presence of hiding places for less aggressive fish, water temperature, oxygenation, and other things.  A rule of thumb is that freshwater aquariums can hold 1 inch of fish per gallon.  Saltwater aquariums can hold 1/2 inch of fish per gallon.

New Fish Aquarium

When adding new fish to a fish aquarium, it is best to gradually introduce them to the aquarium.  If you have extremely valuable fish, the best approach is to have a “quarantine” tank that new fish are held in for 1-2 weeks.  This will allow any diseases that they may be carrying to become obvious before they are introduced to the main tank.


It will also make it easier to treat any problems that do arise.  Treatment with 1-2 ml formaldehyde and 250 mg metronidazole per 10 gallons of water can remove parasites that commonly infect fish.  Treat the fish for 8 hours and then change the water completely.


If a quarantine tank is not an option, it is recommended to at least allow the water temperature to equilibrate by floating the bag or container the new fish came in within the main tank for 10-15 minutes before releasing them.



Setting up a New Fish Aquarium

The time period when a new fish aquarium is set up is one of the most critical times for water quality.  There is a 2-4 week “conditioning” or “run in” time that is needed before water quality stabilizes.  fish aquarium Basically, it takes time for a healthy population of denitrifying bacteria to develop that can degrade the metabolic waste products of the fish in the tank.  This is true regardless of the filtration system used.  All tanks need a biological filtration system.


There are several ways to minimize the run-in period.


  • Only add a few fish and perform frequent water changes (1-2 times a week).


  • “Seed” the tank with bacteria by using gravel from another tank (about 20% of the total added), or a foam filter that was just taken from another tank (if it is allowed to dry out, the bacteria will die).  This doesn’t transmit pathogenic bacteria, as they are usually free in the water or attached to the fish, rather than to the gravel.


  • Use hardy fish initially, such as tetras or goldfish.


  • Test ammonia levels and change as needed.


  • Use commercially available ammonia absorbers.

Fish Aquarium Diet

Because of the extremely wide range of fishes available to fish aquarium owners, their dietary needs vary widely.  Fish may be carnivores (eating mostly other animals), herbivores (eating plants), or omnivores (eating both plant and animal).  Goldfish and bottom feeders are omnivores.


Tropical fish fall into all categories.  Good quality commercial fish foods will generally provide for the needs of most fish Aquarium, however, it is a good idea to consult a fish Aquarium to determine your fish’s dietary habits to determine if supplementation is needed.  Be sure to purchase the commercial fish food appropriate for the species you are using.


Goldfish food is different than tropical fish food.  Supplements like shrimp or tubifex worms may be needed if you have a lot of carnivorous fish in your fish Aquarium.  Herbivores like Pleicostomus may only need the algae growing in the tank.  However, if your tank doesn’t have a lot of algae, a supplement like lettuce may be needed.  Any fresh supplements should be removed periodically if not eaten.


How much do you feed the fish?  The rule of thumb is to feed no more than will be eaten in 15 minutes.  Feed 2-3 times daily.  Excess food will simply decompose in the bottom of the tank and add to the ammonia burden of the tank.  Bottom feeders like goldfish and catfish will consume some of this, but not enough to overcome overfeeding.



Because fish need to eat frequently, and because of the rotting food problem just described, “loading up” a tank with food prior to vacation will likely result in problems when you return.  Vacation feeders work OK but generally are not ideal.  It is recommended that over vacations you arrange to have someone come in and feed you fish daily rather than rely on other means.  Large fish may survive several days without any food, however, smaller fish Aquarium has a higher metabolic rate and will not do well.


Health and Disease

Disease management in fishes is particularly difficult for the fish Aquarium owner.  Despite the advice given in pet stores, most diseases cannot be diagnosed simply by looking at the animal.  That doesn’t work for any other animal or for humans, why should it work for fish Aquarium?  True disease diagnosis will require a veterinarian and some diagnostic tests.


A diagnosis is needed to arrive at the best treatment plan.  Because of the low cost of fish compared to the high cost of a visit to the veterinarian, and because expertise in fish medicine is rare among veterinarians, this leaves you back at the pet store or consulting a reference trying to diagnose your fish’s problem by sight.





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