3 Keys to a Well-Stocked Tropical Fish Tank

Tropical fish tank

A healthy well-stocked tropical fish tank can add life and color to any room in your home or business. Stocking an aquarium properly can be difficult at times. When looking to stock your tropical fish tank there are three principles that you should use to safely and effectively stock your tank: timing, size, and selection.


It takes time to build a well-stocked and healthy aquarium. In new tanks particularly adding fish too quickly can result in some or all of your population dying. Fish waste contains both ammonia and nitrites, these can build up and kill fish quickly. Luckily, bacteria that break down the waste grow naturally in fish tanks. It is essential to give the bacteria enough time to establish themselves before adding lots of fish. At first start with two or three hardy fish. Test the water for nitrites and ammonia. Wait until the levels drop back to almost zero before adding more fish. Remember this spike in waste will occur every time you add new fish. Add fish slowly, only a few every two weeks once established, for a health tank.


It is essential to avoid overstocking your tropical fish tank. Too many in too small a space can cause problems for your filtration systems, tank ecosystem, and population. If your tank is overcrowded, the natural tank bacteria will be unable to effectively break down the fish waste. This can lead to sick or dying fish. Another danger of overstocking your tank is insufficient oxygen. Your fish breath oxygen dissolved in the water. The larger the tank, the more water to absorb oxygen. The primary rule of thumb is one inch of fish per gallon of water. This means if you have a 20 gallon tank, you can have roughly twenty inches of fish.


The next thing to consider is what species to add to your tank. It is important to consider both the species and the aggressiveness of the fish. Some types of fish, male Bettas, for example, are so aggressive that they must be kept alone. Aggressive species are often beautiful but before adding them to an aquarium make sure that they will get along with the other fish. Some species simply do not do well together. Selecting mostly docile fish will help keep your aquarium peaceful. Along with fish, a selection of plants, decoration, or large rocks with hiding places is often a good idea. This not only adds additional visual appeal to your tank but gives the less aggressive fish a place to seek shelter if attacked.

Follow these three principles and you’re well on your way to a beautiful, healthy, and well-stocked tropical fish tank.

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