Different aquarium tank sizes are purchasable in stores and online. The larger the aquarium becomes, the thicker the glass needs to be to hold in the aquarium’s pressure. Simultaneously, the weight also increases due to the amount of water inside. This chart provides information on the dimensions, empty weight, and roughly estimated full weight of the most common standard glass aquariums available. Fish tank sizes will determine what species of fish, reptile or, amphibian you’ll be able to keep. If you own a fish tank and do not know its dimensions, check out the Aquarium Volume Calculator which will help show you how many gallons your aquarium is.
Small Aquariums
Small aquariums are quite commonly kept on office desks, countertops, aquarium stands, and many other surfaces. Regardless, furniture weight limitations should always be considered when setting up an aquarium. Small aquariums should not have a problem being kept on the second story of a house because they are not incredibly heavy when full.
The challenge with keeping smaller aquariums, especially for newer hobbyists, is that the aquarium is more prone to swinging water parameters. For example, feeding a little too much food or keeping to many fish that produce a lot of waste can cause nitrates and phosphates to skyrocket which interrupts the aquarium’s balance. It is very important to monitor the water parameters of smaller aquariums closely. The incredibly small 5 gallon aquarium is great for counters and small spaces but will be the hardest to maintain due to its small size. The larger the aquarium is, the more resilient it is to swinging parameters because of the increased volume of water inside.
In fish tanks on this scale, it is normally recommended to also keep only smaller species of fish. Tetras, betta fish, pea puffers and rasboras are a few freshwater fish that can be kept in fish tanks of this size. Also, marine animals such as; gobies, coral, anemones and much more can also thrive in small aquariums. Great amounts of fish keeping experience is recommended before attempting to keep saltwater fish in these nano systems.
| Aquarium Size | Dimensions | Empty Weight | Full Weight |
| 5 Gallons | 16″x8″x10″ | 7 lbs | ~62 lbs |
| 10 Gallons | 20″x10″x12″ | 11 lbs | ~111 lbs |
| 15 Gallons | 24″x12″x12″ | 21 lbs | ~170 lbs |
| 15 Gallons (tall) | 20″x10″x18″ | 22 lbs | ~170 lbs |
| 20 Gallons | 24″x12″x16″ | 25 lbs | ~225 lbs |
| 20 Gallons (long) | 30″x12″x12″ | 25 lbs | ~225 lbs |
Medium Aquariums
Medium sized aquariums may be a bit harder to place on countertops or tables. They will most likely need a designated aquarium stand in order to be stable. Fish tanks between 29 and 40 gallons are excellent sizes for new hobbyists. They’re not incredibly large which may cost quite a lot of money, they don’t take up an incredible amount of space unlike a 150 gallon aquarium, and swinging water parameters are much smaller as compared to a small 5 gallon aquarium.
The weight of 55 and 65 gallon aquariums should not be taken lightly. Weight should be really considered when placing these larger sized fish tanks in older homes and on upper stories of homes. Most homes should be able to sustain the weight of these fish tanks but it is definitely better to double check rather than have a fish tank crashing through your ceiling.
Fish tanks at this size can house larger freshwater fish, like larger species of gourami, goldfish, and medium sized cichlids. Clownfish, dwarf angels, and wrasses are a few examples of marine fish that would do well in saltwater aquariums at this size.
| 29 Gallons | “30×12″x18” | 40 lbs | ~330 lbs |
| 30 Gallons | 36″x12″x16″ | 48 lbs | ~350 lbs |
| 40 Gallons | 36″x18″x17″ | 58 lbs | ~458 lbs |
| 55 Gallons | 48″x12″x21″ | 78 lbs | ~625 lbs |
| 65 Gallons | 36″x18″x25″ | 126 lbs | ~772 lbs |
Large Aquariums
| 75 Gallons | “48×18″x21” | 140 lbs | ~850 lbs |
| 90 Gallons | 48″x18″x25″ | 160 lbs | ~1050 lbs |
| 125 Gallons | 72″x18″x23″ | 206 lbs | ~1400 lbs |
| 150 Gallons | 72″x18″x29″ | 308 lbs | ~1800 lbs |
| 180 Gallons | 72″x24″x25″ | 338 lbs | ~1900 lbs |
| 210 Gallons | 72″x24″x29″ | 343 lbs | ~2180 lbs |
Last, are the large aquariums. It is not recommended to keep these aquariums on the upper story of houses due to their immense weight. Fish tanks that are 125 gallons or larger may also need additional reinforcement on floors in order to be safely placed inside of a home. Water parameters are much easier to control in fish tanks this size and these aquatic enclosures will also allow fish keepers to house fish of many different sizes.
Large freshwater animals such as oscars, peacock cichlids, and eels can be housed in fish tanks this large. There are many more types of marine fish that can be kept in aquariums this large, such as: tangs, rabbitfish, and puffers. There are many more fresh and saltwater creatures that can be considered. I only wanted to name a few to give an idea as to what can happily thrive in fish tanks of this caliber.
Big aquariums unfortunately come with a cost. The glass itself will cost more because of its thickness and size. Also, aquariums of this size will most likely require more lighting, different filtration, and circulation of some sort. All of this will lead to larger water and electric bills. Please take that into consideration when setting up aquariums of this size.
Final Notes
Medium sized aquariums are a great place for new aquarists to dip their toes in the hobby. Even fish tanks that are 20 gallons are a safe bet for starter fish keepers. Anything smaller may get a little more challenging because of swinging water parameters and anything larger may become overwhelming with cost, especially for anyone just starting their first fish tank. At the end of the day, jumping in and enjoying the hobby is all that matters!
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