from the blog

How to Determine the Right Number of Fish for Your Aquarium

Caring for fish

September 30, 2020

Stocking a fish tank may seem like an easy enough task – you simply go to the pet store, pick out the fish you like and bring them home. If this is the procedure you follow when stocking your tank, however, you should not be surprised if you encounter problems down the line. There are a variety of factors that should play into your decision regarding not only what type of fish you put in your tank, but the number of fish as well. If you overstock your tank, it could increase the biological load past the point that your beneficial bacteria can handle. When this happens, the water quality in your tank could drop, your ammonia levels could skyrocket and all of those new fish you just brought home may end up dying. To prevent this from happening, do your homework to be sure you stock your tank properly the first time you do it.

Important Factors to Consider

When deciding how many fish to keep in your tank, the number one factor to consider is of course, tank size. It should go without saying that large fish tanks are capable of accommodating a greater quantity of fish than smaller tanks, but this is not the only factor to consider. You must also think about the size of the fish you intend to stock your tank with. Beginning aquarium hobbyists are often encouraged to follow the “one inch of fish per gallon” rule. This rule is by no means perfect, but it is a good place to start. To follow this rule, take the full length of each fish at maturity and factor it into the gallon capacity of your tank. If you have a 30-gallon tank, for example, you could safely house fifteen fish that grow to a maximum of 2 inches in length. As it has been mentioned, this rule is not perfect. It does not account for the fact that some fish are more full-bodied than others and thus take up more space, nor does it account for the fact that some fish produce more waste than other species.

Tips for Stocking Your Tank

In order to properly stock your tank, it is wise to strive for a balance in the number and type of fish you purchase. Do not fill your tank with full-bodied fish like cichlids – rather, try to create a community tank using several different species. This may require you to purchase smaller numbers of fish but it will lead to greater harmony in your tank in the long run. You should also keep in mind that many tropical fish are schooling species and should be kept with no fewer than three of their own kind. If you plan to keep multiple species in your tank, be sure you do not overstock your tank just to meet the schooling needs of certain species. It is better to under-stock your tank at first and then to slowly add more fish, giving your tank and your current set of fish, time to acclimate.

Balance is the key to keeping an aquarium clean and healthy – a tank that is properly stocked is more likely to be in balance than an overstocked tank. In order to help your tank achieve that balance, consider adding an EcoBio-Stone to give your tank an extra boost in handling the biological load of your tank. EcoBio-Stones are made from porous volcanic rock and cement that has been infused with beneficial bacteria. Once introduced into your tank, these bacteria will multiply and immediately begin working to break down waste products and toxins in your tank, making it a cleaner and healthier environment for your fish. Over time, you will learn how many fish your tank can handle and the beneficial bacteria in your tank will adjust to any additions you make to keep it running smoothly.