How Do You Know When Your Aquarium Has Too Many Fish?

Ideal habitats should provide enough space for species to feel comfortable and live healthy lives. When a habitat becomes overcrowded, species not only run out of space for their instinctive activities but also start competing for resources. At the same time, the byproducts and waste they create will start to accumulate, thus resulting in health hazards. In the aquarium hobby, overstocking is the term used to describe an ecosystem compromised by the presence of too many species. When you introduce too many fish, plants, and invertebrates to a tank or garden pond, this is known as overstocking, and it can result in a headache for fish keepers. The friendly staff at Aquatic Warehouse would like to share some details on how to tell when your aquarium is overstocked with fish.

Adequate Stocking Rates

One of the golden rules of fish keeping is related to the proper stocking rates of tanks or ponds. At its most condensed level, the golden rule of stocking tanks boils down to an average of one inch of fish per gallon of water. For garden ponds, the rule is one inch per 10 gallons. These rates are based on two species: goldfish for tanks and koi for ponds. Naturally, aquarium ecosystems are typically more diverse, but it’s important to note that both koi and goldfish are known to be messy eaters that create plenty of waste, which in turn increases the overall biological load. For this reason, the golden rule is safe to apply. All bioloads can be increased with larger filtration by volume.

What Happens When an Aquarium Is Overstocked?

Let’s say you took a couple of months to establish a planted 20-gallon freshwater tank. The next sensible step would be to introduce one or two hardy species to achieve bacterial bloom and fully complete the nitrogen cycle. After a week of seeing your fish swim and feed happily in zero-ammonia water, this would be a good time for stocking, but you wouldn’t want to immediately introduce two danios, a school of neon tetras, two angels, five mollies, and two Corydoras. If you do this, you’ll see ammonia levels jump a couple of days after a water change, and the fish might start becoming aggressive.

Overstocked Tanks in Aquarium Shops

At some pet stores that sell aquarium species, it’s not uncommon to see tanks holdings a lot of zebra danios, rainbow sharks, and other colorful fish. This explosion of color in a single tank makes sense from a marketing standpoint. It isn’t the most ideal for species therein, but the shop managers hope they’ll sell quickly. These shops are able to overstock tanks because employees are doing 50 percent water changes on a nightly basis, and they have the added benefit of industrial-grade aeration and filtration systems.

Dealing with Overstocking

You can never go wrong by giving fish as much space as possible in their tanks or ponds. Even if you upgrade the pumping and filtration system, there’s still the matter of constant cleaning and water changes, which can stress aquarium species that are already running out of space. The best option is to either get a larger tank or reduce the stocking level.

In addition to making sure you don’t overstock your tank or pond, you also need all of the essential supplies to properly maintain your aquatic environment. At Aquatic Warehouse, we carry everything you need for your aquarium or pond, whether it’s beneficial bacteria, protein skimmers, aeration products, pond filters, or any other supply. You can order what you need from your website or come pick it up in person at our store in Kearny Mesa. If you have any questions, don’t hesitate to give us a call today at 858-467-9297.