How Big Do Rasboras Get?

Rasboras typically grow to be between 2 and 4 inches in size. The type of rasbora determines how big it will grow. Furthermore, some rasbora species, like harlequin rasboras, grow more rapidly than others. Rasboras typically reach adult size within 9 months of hatching. 

If you want to know how big different types of rasboras get and how many rasboras you can keep in a tank, you are at the right place! Furthermore, you may wonder how much space a rasbora needs, which we will also discuss here.

How Big Do Different Types Of Rasboras Get?

Rasboras are tiny fish, growing to be between 2 and 4 inches long. Of course, the type of rasbora plays a big role in how big that fish will get. It also determines how big a tank you need for it.

There are many kinds of rasboras, including galaxy rasboras, harlequin rasboras, and chili rasboras. Let’s consider how big these seven types of rasboras get.

Galaxy Rasboras

Galaxy rasboras are one of the smaller rasboras, growing to be only about an inch when fully grown. As a result, galaxy rasboras don’t require as much space as some other rasbora species, and you can keep them in a 10-gallon tank if you wish.

Due to their small size, galaxy rasboras are also fast growers. However, it takes a rasbora fry about 3 months to reach maturity after hatching.

Scissortail Rasboras

Scissortail rasboras are significantly bigger than other rasboras. In the wild, they can quickly grow as big as 6 inches. However, most aquarium scissortail rasboras reach about 3.5 inches in length.

Due to their bigger size, it’s natural to assume that you also need more space for them. Scissortail rasboras need at least a 20-gallon tank to thrive and reach their full size when adults. Scissor rasboras take between 6 and 9 months to reach maturity.

Scissortail Rasbora in Front of Plant

Harlequin Rasboras

Harlequin rasboras are another fast-growing type of rasbora. They require only about 3 months to reach maturity from hatching. Harlequin rasboras are also smaller than some other rasboras, aiding in their rapid growth.

Harlequin rasboras grow to about 1.75 to 2 inches long. Therefore, they are the perfect size to keep in a small to a medium-sized aquarium. Harlequin rasboras need at least a 10-gallon tank to thrive.

Several Harlequin Rasboras from the Side


Blackline Rasboras

Blackline rasboras are quick swimmers, typically hardier than some other rasboras, not caring for the water quality as much. Blackline rasboras grow to about 2.5 inches long, placing them in the medium category for rasboras.

Because they love to dart from one side of the tank to the other, you’ll need an aquarium of at least 15 gallons to satisfy them. Blackline rasboras usually take about 6 months to reach maturity.

Chili Rasboras

Chili rasboras are some of the most striking rasboras to keep in your aquarium since they have bright red and pink colored skin. However, these nippy little rasboras are some of the smallest you may ever own.

Chili rasboras only grow to about 0.75 inches long in captivity, meaning they are extremely small even as adults. Furthermore, chili rasboras are known to be fast-growing since they only have so much growing to do. They take about 3 to 6 months to reach maturity.

Dwarf Rasboras

Dwarf rasboras are also known as pigmy rasboras, and these interesting-looking redfish can transform the aesthetic of your fish tank. But, despite the name, dwarf rasboras aren’t as small as you may think.

Adult dwarf rasboras grow to about 1 inch long and grow relatively quickly, reaching full maturity in about 3 to 6 months after hatching. Dwarf rasboras need a 5-to-10-gallon tank.

Clown Rasboras

Clown rasboras are a lot bigger than other types of aquarium rasboras. They can grow to about 4 inches in captivity. Furthermore, they need at least a 60-gallon tank to keep them happy and satisfied.

Clown rasboras are red-colored and have random spots on their scales and fins. Clown rasboras are peaceful fish, but the pH levels required for tank water may make it challenging to find suitable tank mates.

They reach maturity within 6 to 9 months of hatching.

How Many Rasboras Should You Keep In A Tank?

In addition to considering the tank size required for your rasboras, you should also know how many you can keep in a tank.

Rasboras are schooling fish, meaning they fare best when kept in groups. Having only one or two rasboras may cause them to become stressed or ill.

Most rasboras prefer to be in schools of at least six. This means having no less than six of one type of rasbora in your tank. You must ensure that the tank is big enough to sustain six rasboras, or they will start to fight.

Moreover, every male in a tank should have at least two female rasboras. If not, the males will start to compete for the females’ attention, which may lead to fighting and fin nipping.

Therefore, you must consider the number, and gender, of the rasboras you keep in a tank. Too many, and they may feel overcrowded. Too little, and they will feel lonely and may become depressed.

By ensuring all their conditions are met, you will have healthy and happy rasboras in your tank that can grow to their full size and live to their life expectancy.