Have you ever imagined the beautiful environment of the Sea close to your home in your living room? A 100-gallon fish tank is ideal for placing the foundation for an incredible home aquarium. But before getting to the point of focus, the choice of inhabitants is obligatory. All your questions about 100-gallon fish tank stocking ideas will be shown in this guide, including information about tank sizes and capacities, as well as the best fish species and how many can be comfortably accommodated in such a large 100-gallon fish tank aquarium.
We will be able to even show you the number of goldfish that should be in one tank for the best environment. Well, let’s get right back to work as we transform your 100 gallons into an amazing aquatic garden!
100-gallon fish tank stocking ideas
How Big Is a 100-Gallon Fish Tank
A 100-gallon fish tank’s size depends on its shape. Here’s a breakdown of common shapes:
Rectangular Tank
This is the most popular shape. To find the dimensions, we can divide the volume (100 gallons) by the desired aspect ratio (100-gallon). A common aspect ratio is 4:2:2 (100-gallon).
Converting gallons to liters: 100 gallons * 3.785 liters/gallon = 378.5 liters
Sample Calculation (4:2:2 aspect ratio)
Length (L) = Volume / (Aspect Ratio for Length x Width x Height)
| L = 378.5 liters / (4 x 2 x 2) | L = 47.31 inches (rounded to two decimal places) |
| Height (H) = L / 2 = 23.66 inches (rounded) | Width (W) = L / 2 = 47.31 inches / 2 = 23.66 inches (rounded) |
Cube Tank
All sides of a cube tank are equal.
| Dimension (each side) = ³√Volume = ³√378.5 liters ≈ 7.23 inches (rounded to two decimal places) |
Round Tank
Round tanks are less common for large sizes due to limitations on viewing area. Their volume is calculated differently, so it’s best to refer to the manufacturer’s specifications for size.
Table Summary
| Shape | Dimensions (inches) | Volume (liters) |
| Rectangular (4:2:2) | L: 47.31, W: 23.66, H: 23.66 | 378.5 |
| Cube | Side: 7.23 | 378.5 |
| Round | – | 378.5 (refer to manufacturer’s specifications for actual dimensions) |
Best Aquarium Fish for a 100-Gallon Tank
Angelfish
| They are one of the magnificent freshwater fish which are available in different colors and patterns, and they are generally not aggressive. They are tall fish that have angel fin-shaped bodies, and the tallest of them can grow up to 6 inches in height. |  |
Discus
| Discus fish are one of the most beautiful freshwater fishes and are known to be very calm and docile fish. These fish are warm-water fish that do well under good water conditions. They are 6 inches long and should be kept in groups of 5 or 6. |  |
Severum
| Severums are another beautiful and peaceful fish that would do well in a 100-gallon tank. These Central American cichlids are found in red, green, and gold, and can reach a length of 8 inches. |  |
Rainbow Shark
| A rainbow shark is an even active fish with an elongated body and a single line of iridescent color on the lateral line. Most of them are quite passive but can become aggressive with other fish that also inhabit the lower regions of the aquarium. Rainbow sharks grow up to 6 and a quarter inches in length. |  |
100 Gallon Fish Tank Stocking Ideas
Here are some stocking ideas for a 100-gallon tank, keeping in mind the fish mentioned earlier.
Community tank with schooling fish
| Neon Tetra (20) | Corydoras catfish (8) |
| Cardinal Tetra (15) | Honey Gourami (1) |
This is an elegant option that will not require much attention from you. The neon and cardinal tetras shall form schools and would be spectacular to watch for, while the Corydoras catfish would feed on the leftover food at the base of the aquarium. The honey gouramis are easy-going fish that you can place in the center of your aquarium and enhance their color.
Large centerpiece fish with smaller community fish
| Angelfish (4) | Kuhli Loach (10) |
| Harlequin Rasbora (20) | Bristlenose pleco (1) |
This stocking idea involves a group of angelfish to be the focus of the show. Select angelfish bred in an aquarium as opposed to those caught in the wild, which are more aggressive. The harlequin rasbora is another colorful fish that is schooling and will contribute to the activity level of the aquarium. The kuhli loach is an easygoing fish that moves around at the bottom of the tank and helps to clean it. The Bristlenose Pleco is another algae eater fish that will prove useful in maintaining the cleanliness of the fish tank.
Species tank for a single fish or group of fish
| Discus (6) | Apistogramma (breeding pair) | Dwarf cichlids (group of 6-8) |
Species tanks are particularly good when used in a manner that shows off a certain type of fish. Discus are colorful and calm fishes that can only live in very clean water. Apistogramma is a group of small and bright cichlids, which do not require complex conditions to be provided for them. Another type of small cichlids is dwarf cichlids, which are found in different colors.
100 gallon fish tank aquarium
How Many Goldfish Can You Have in a 100-Gallon Tank
A 100-gallon tank can hold several goldfish, but the exact number depends on the type of goldfish.
Fancy Goldfish
Big goldfish like orandas, ruins, and moor goldfish require more space because of their body structures and metabolism which produce more waste products. So, a bunch of fancy goldfish should be provided with at least 20 gallons of water each when they grow up. Therefore, a 100-gallon tank would ideally be suitable for housing 4 – 5 fancy goldfish.
Common Goldfish
Comet and shubunkin are two types of common goldfish that grow bigger and are more active swimmers as compared to others. They require even more space compared to the fancy goldfish, at least 50 gallons of water per fish once they grow up. Hence, a 100-gallon tank would not be adequate for standard goldfish in the long run.
Final Thoughts
This article offers a step-by-step procedure on how to stock a 100-gallon fish tank. It ranges from the size of the tank to the type of fish most often found in tanks, ideas for stocking the tank, be it a community tank, a centerpiece, or a species tank. Notably, we focus on the requirements of goldfish and how many can be accommodated in a 100-gallon tank. If properly planned for, you can have a stunning and healthy underwater environment in your home.
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