Aquarium Stock Calculator

Aquarium enthusiasts, are you tired of manually calculating the appropriate stocking levels for your aquarium? Or are you a beginner unsure of where to start when it comes to adding fish to your tank? Look no further! Our Aquarium Stock Calculator is here to simplify the process and ensure your underwater world is thriving. With just a few inputs, our calculator will determine the optimal number of fish for your tank size and water parameters, taking into account species compatibility and growth potential. Say goodbye to the uncertainty and stress of guessing at stocking levels - trust us, and your fish will thank you!

Aquarium Stock Calculator

Calculate the stock level for your aquarium.

Aquarium Stock Calculator Results
Tank Volume (in gallons)0
Number of Fish0
Number of Invertebrates0
Number of Plants0
Stock Level0

When planning an aquariums fish stock, our aquarium stock calculator complements the aquarium volume calculator. Together, they help you determine suitable fish populations for your tank.

How to Use the "Aquarium Stock Calculator"


The "Aquarium Stock Calculator" is a valuable tool for aquarium enthusiasts to determine the appropriate stock level for their aquarium. This calculator takes into account the tank volume, number of fish, number of invertebrates, and number of plants to provide a stock level assessment. By utilizing this calculator, aquarium owners can ensure a healthy and balanced environment for their aquatic pets.

Instructions for Utilizing the Calculator

To effectively use the "Aquarium Stock Calculator," follow these steps:

  1. Tank Volume (in gallons): Enter the volume of your aquarium in gallons. This information is crucial as it serves as the basis for calculating the stock level. It determines the amount of water available for the fish, invertebrates, and plants.
  2. Number of Fish: Specify the quantity of fish you have in your aquarium. Each fish is considered to be approximately 1 inch in length for simplicity in this calculator. It is important to provide an accurate count to ensure an accurate assessment of the stock level.
  3. Number of Invertebrates: Indicate the number of invertebrates, such as snails or shrimp, present in your aquarium. Similar to fish, each invertebrate is assumed to be approximately 1 inch in length. This information helps determine the invertebrate stock level.
  4. Number of Plants: Enter the number of plants in your aquarium. Plants play a vital role in providing oxygen to the water, allowing for increased stock levels of fish and invertebrates. Each plant contributes an additional 0.5 inches of stock level for fish or invertebrates.

Once you have filled in all the required input fields, click the "Calculate Stock Level" button.

Output Fields and Interpretations

After clicking the "Calculate Stock Level" button, the "Aquarium Stock Calculator" will generate the following output:

  1. Tank Volume (in gallons): This field displays the tank volume value you provided.
  2. Number of Fish: The calculator shows the number of fish you entered.
  3. Number of Invertebrates: This field represents the count of invertebrates you specified.
  4. Number of Plants: The calculator displays the number of plants you entered.
  5. Stock Level: This field reveals the calculated stock level of your aquarium. The stock level is expressed as a decimal value and provides an assessment of the balance between the volume of water and the number of fish, invertebrates, and plants in your aquarium.

The stock level value will be either "Overstocked" or "Properly stocked." If the stock level is greater than 1, indicating an excess of livestock compared to the tank volume, it will be labeled as "Overstocked." If the stock level is equal to or below 1, indicating a suitable balance between the livestock and tank volume, it will be labeled as "Properly stocked."

"Aquarium Stock Calculator" Formula

The "Aquarium Stock Calculator" determines the stock level using the following formula:

  1. Calculate the stock for fish: Number of Fish * 1 inch
  2. Calculate the stock for invertebrates: Number of Invertebrates * 0.5 inch
  3. Calculate the stock for plants: Number of Plants * 0.5 inch (extra stock per plant)
  4. Calculate the total stock: Sum of fish stock, invertebrate stock, and plant stock
  5. Calculate the stock level: Total Stock / Tank Volume

The stock level is then rounded to two decimal places for better readability.

Illustrative Example

Let's consider an example to demonstrate the usage of the "Aquarium Stock Calculator." Suppose you have a tank with a volume of 20 gallons, 5 fish, 2 invertebrates, and 3 plants. By inputting these values into the calculator, you will receive the following results:

  • Tank Volume (in gallons): 20
  • Number of Fish: 5
  • Number of Invertebrates: 2
  • Number of Plants: 3
  • Stock Level: 0.50 (Properly stocked)

According to the calculated stock level, your aquarium is properly stocked, as the stock level is within the recommended range.

Illustrative Table Example

Here's a table example with various data inputs to showcase the "Aquarium Stock Calculator" in action:

Tank Volume (in gallons)

Number of Fish

Number of Invertebrates

Number of Plants

Stock Level

308420.40 (Properly stocked)
102100.30 (Properly stocked)
5012640.44 (Properly stocked)
153120.26 (Properly stocked)

Each row in the table represents a different combination of tank volume, number of fish, number of invertebrates, and number of plants. The stock level is calculated for each scenario, indicating whether the aquarium is properly stocked or overstocked.


The "Aquarium Stock Calculator" is an essential tool for aquarium owners to determine the appropriate stock level for their aquarium. By inputting the tank volume, number of fish, number of invertebrates, and number of plants, you can ensure a balanced environment for your aquatic pets. Properly stocking your aquarium helps maintain a healthy and thriving ecosystem. Utilize the "Aquarium Stock Calculator" to make informed decisions about the number of fish, invertebrates, and plants suitable for your aquarium's size. Happy fish-keeping!

About the Author

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Tasfin Jannat

Tasfin Jannat is a Bangladeshi aquarist who has been keeping and breeding fish for the past 4 years.