Schooling is an important social behavior for fish in an aquarium environment. Fish that typically travel in schools in the wild need to experience that same level of community and protection in captivity. Rasboras are one such fish that live in schools ‒ but you might be wondering whether one type of Rasbora will accept another type living in its group.
So, will different Rasboras school together? Yes, different Rasboras will typically school together. Although different kinds of Rasboras may restrict schooling to other members of their specific species, most Rasboras will typically school together if kept in the same tank.
There is no hard rule when it comes to which types of Rasboras will school together. Fish schooling is still a behavior that science is very much in the dark about, and Rasbora schooling preferences seem to be based on the whims of the individual fish involved. The rest of this article will dive into Rasbora schooling behaviors and how you can encourage different Rasboras to school together.
Schooling is a scientific term used to describe the behavior of fish “swimming in the same direction in a coordinated manner.” This term is closely related to shoaling, which is used to describe any group of fish that stick together for social reasons.
Rasboras are one kind of fish that school and shoal together, and they do so for a variety of reasons:
- Schooling provides increased protection against predators. Traveling in a group makes it more likely that a single Rasbora will be able to detect a predator and alert the rest of the group. It also protects the Rasboras from attacking predators because the large number of Rasboras makes it less likely that any individual member will fall prey to a predator.
- Schooling makes it easier for Rasboras to find mates. A member of a school of male and female Rasboras will have a much less difficult time finding a mate than a lone Rasbora desperately searching for a member of its species in the vast emptiness of open water
- Schooling provides an easy source of socialization, which can decrease stress levels and contribute to overall health. Studies have found that shoaling fish that are separated from their schools have an increased respiratory rate, which is likely due to the agitation and stress of being separated from the school.
- Schooling also makes it easier to find food. More eyes searching for food means a school of Rasboras is better at finding something to eat than a single Rasbora would be.
When you add different kinds of Rasboras to the same tank, the hope is that they will instantly be drawn to each other and start schooling together. Reality does not always follow our expectations though, and you might find your Rasboras playing it safe and sticking to their own species.
If your Rasboras don’t instantly start schooling together, there’s a good chance they never will. However, if you’re particularly determined to get different Rasboras to school together, there are a few things you can try.
If your Rasboras aren’t schooling, one of the first things you should try is increasing the tank size. If you have a smaller tank, there might simply not be enough room for your Rasboras to comfortably group and swim together.
This is especially true if you have a large number of two or more Rasbora species. Rasboras will inherently be drawn to school with their own species over Rasboras of another species. If your tank is on the smaller side, two groups of Rasboras who might otherwise school together could remain separate due to the size limitations of their environment.
Most schooling fish are less likely to remain in their schools if they encounter an area of dense plant growth or other obstacles. They are more likely to separate and hide in the plants than they are to keep swimming around together. Scientists aren’t sure why this is the case, though there are a few possibilities:
- More plant growth and decorations means less room for your Rasboras to comfortably swim around in.
- The presence of a dense field of obstacles may trigger a survival response in your Rasboras. Predators may be lurking amongst the plants, and the Rasboras may feel safer hiding in the shadows than swimming around openly.
So if the bottom of your tank is covered with plants and decorations, you might want to remove some of them to incentivize your Rasboras to begin schooling together. This can also be addressed by getting a bigger tank. Unfortunately, upgrading your tank size can be prohibitively expensive. If you don’t have the cash to drop on a larger aquarium, removing existing plants and decorations is a quick money-saving alternative.
As I mentioned earlier, one of the main reasons Rasboras school together is to protect themselves from predators. Your Rasboras might not be schooling together because they feel safe in your tank. If you’ve selected the fish in your community correctly, there probably isn’t anything trying to eat your Rasboras. This lack of predators can put them at ease, especially if they’ve been living in your aquarium for awhile.
Now, I’m not telling you to add a predator to your tank just to make your Rasboras freak out and school together. That would be rather cruel, and you would probably have to buy more fish to replace the ones that became meals. However, you can simulate the addition of a predator to your tank by adding a completely docile larger fish.
This should be relatively easy, as most Rasboras max out at 2 inches. There are plenty of docile fish in the 4-6 inch range that can push your Rasboras into schooling together without the risk of becoming a meal.
While Rasboras will most commonly school with other Rasboras, they may feel comfortable schooling with other kinds of fish as well.
There’s no guarantee that your Rasboras will gravitate toward schooling with other fish. However, if you’d like your Rasboras to school with the other fish in your community, there is a way you can increase the likelihood of this happening.
One of the primary reasons fish of the same species school with each other is that they look alike. A phenomenon called the Oddity Effect contributes to this preference. Basically, when predators look at a school of fish, they are drawn to any fish that stands out from the pack. By surrounding themselves with other fish that look like them, individual Rasboras are better defended because predators won’t single them out.
So if you can find other types of fish that are similar in shape, size, and color to your Rasboras, you can increase the likelihood of these fish schooling together. This can be difficult even with a large tank, minimal plant growth, and a larger simulated predator though ‒ so don’t be surprised if your Rasboras stay away from another type of fish that looks exactly like them.