Betta fish are very popular in the aquarium hobby. They are small, colorful and easy-to-care for.
More importantly: They are one of the few fish that can be kept in a small space like a 5 gallon tank.
This does limit what choices you have for tank mates, however.
The best tank mates for bettas in a 5 gallon tank are brigittae rasboras, ember tetras, strawberry rasboras, and ramshorn snails. Avoid fish that get too large or aggressive ones that might get into fights with your betta. Also, avoid putting any other betta into the aquarium – male or female.
Let’s discuss a few more options you have.
(Note that pretty much every item on this list – including your betta – would benefit from being in a 10 gallon aquarium, but I’m going to assume you know that and can’t keep anything larger than a 5, so I’m not going to harp on this point in the article.)
We’re going to start this list off on a bit of a controversial note. Common wisdom is that you should keep pygmy corydoras in at least a 10 gallon aquarium so they have enough room to swim.
That having been said, I’ve heard from quite a few people who have successfully kept these fish in 5 gallon aquariums, and Tropical Fishkeeping has them as 5+ gallons on their profile page.
I would say, however, that you should only add them to a landscape 5 gallon, not a portrait or cube one. You want to maximize the floor space they have to swim around in.
Also, if you’re adding them to a 5 gallon, I’d recommend a group of 5. (No fewer because they need a certain number to feel comfortable and no more for crowding reasons.)
If you can increase the size of the aquarium any, that would of course be better. Otherwise, just make sure to keep a close eye on water quality and your weekly water changes.
Out of the 3 types of pygmy corydora, the habrosus cory is probably the best one, since it stays down at the bottom of the aquarium more, is a bit less active, and acts more like a regular corydora.
Another option for a 5 gallon aquarium with betta is the brigittae rasbora. This is a tiny rasbora that can live in aquariums this size with little issue.
They naturally come from slow moving, blackwater streams in indonesia. This makes them a good choice for bettas, who also don’t like strong current in their water and also can benefit from being in a blackwater aquarium setup.
When adding them to a 5 gallon aquarium, you should add a group of 6 of them. It’s important to try to balance the need to give them a large enough group for them to feel comfortable while at the same time not overpopulating your already small aquarium.
The least killifish (which is actually not a real killifish) is another good option to keep with bettas in a small aquarium like a 5 gallon.
They stay pretty small, but being livebearers means that they will pretty much instantly start trying to breed in your aquarium.
I’m not sure that any fry will make it to adulthood with your betta in the tank to eat them, but you may find yourself having to remove fry from the aquarium at some point in the future.
Alternatively, you can avoid this issue by keeping all males.
Another good potential option is the strawberry rasbora. This is another tiny species of rasbora that looks great and can work in a tank with a betta.
You may see these fish sometimes mislabeled as chili rasbora because the name is more widely recognized, but they’re a different species.
They prefer slow moving water that is slightly acidic and in a tank that is heavily planted.
They are completely peaceful, so you won’t have to worry about them harassing your betta or nipping it’s fins – only whether your betta decides it doesn’t want other fish in its aquarium.
Celestial Pearl Danio
The celestial pearl danio is an interesting looking fish that is typically extremely shy, but if you have enough of them they will feel confident enough to dance.
They can go into 5 gallon aquariums and will work well with bettas temperament-wise, but they do like slightly colder water than bettas do, so that is something you’ll want to consider.
If you’re running an un-heated betta aquarium they might do better than if you’re running a heater.
Still, it’s an interesting fish that is worth mentioning as one of your potential options.
Ember tetras are a small, bright red species of tetra. They are generally peaceful in nature, and they’re small enough that you can put a group of them in an aquarium.
They do prefer to be in larger groups, but I wouldn’t put a group of more than 6-7 in a 5 gallon aquarium. If you go this route, you’ll want to pay closer attention to your water quality so it doesn’t get out of hand.
Ember tetras should eat most anything you feed them including flake foods. They’re relatively hardy, so once you get them set up they should be easy to care for.
Another nano-rasbora you can keep in a 5 gallon aquarium is the phoenix rasbora. This is a small, orange-red rasbora that is peaceful and easy to take care of.
Like the strawberry and brigittae rasboras, they like slow moving, acidic water. They are also often confused for the other two species.
This is probably the best known type of tetra, and you can also keep it in a 5 gallon aquarium. (Although you’re limited to around 3 or 4 of them.)
I’m not sure I would recommend this over the ember tetra, but if you’re more of a neon guy, this is something that may work out in your aquarium.
I would be careful and watch water quality closely, however, as neon tetras get quite a bit bigger than embers do.
This rasbora can get a bit bigger than the other ones on this list, with the largest adults reaching up to 1” long.
They don’t have as bright of coloration, due to them being more translucent, but they do still make a good potential addition to your aquarium. (The exception being the emerald dwarf rasbora, which is a completely different species – and actually a danio, but which looks great and has nice coloration.)
They like PH that’s anywhere between 5-6.5, though usually you can get away with water outside of this range as long as you keep it stable so there are no rapid PH swings.
Ramshorn snails are one of the few snails on this list for 2 reasons:
- Though larger snails like nerites or mystery snails are sometimes recommended for bettas, I don’t like adding them because the betta will constantly harass the snail – trying to eat its eye stalks. In a larger tank that’s well planted this isn’t so much of a problem. In a 5 gallon, it would end badly for the snail.
- Most of the smaller snails you could add don’t look that great and are considered pests.
Ramshorn snails are still considered pests, but they’re pests that come in designer colors. Whether you’re looking for bright red and pink ones, blue ones, ones with stripes, ones with leopard spots, you have a ton of options to choose from.
They will reproduce based on the amont of food in your aquarium (hence why they’re considered pests), but I’ve never had this be a problem in my aquariums.
Your betta may pick one or two off, but since they reproduce by themselves, this shouldn’t be an issue.
They can survive in just about any water conditions and have low bioload, so you don’t have to worry about water quality too much here.
The last snail on this list is the pond snail (or bladder snail – they look very similar and are basically identical in other regards as far as I’m aware).
These snails are plain looking, but their usefulness outweighs their looks by far. They’ll eat algae, leftover food, dead plant matter, and anything else they can get their mouths on and will keep your aquarium clean.
They do reproduce, like ramshorn snails, and in my experience are a lot hardier than ramshorn snails are. Unlike the designer ramshorns, you’ll usually pick them up for free on aquarium plants or driftwood.
What you Need to Know About Introducing Tank Mates to Your Betta
Many people believe that if they have a betta fish, they need to keep it in a tank with other fishes. The truth is that these small, colorful fishes are best kept in an aquarium without any other fish in the tank with them.
Especially in a small tank like a 5 gallon aquarium.
The betta doesn’t need companionship and can thrive in an aquarium without any other fish in it, but if you want to avoid the hassle of having to do all the work of keeping up with 2 tanks and 2 filters, adding some other fish to your betta tank might be something you’re considering.
One thing you have to understand if you’re going to do this is that if you choose the wrong fish to put in, either them or your betta may end up getting killed.
There have been plenty of cases where people have kept their betta with another species of fish successfully for several years, only for the betta to turn one day and start attacking everything else in its tank.
Because of this, you should always have another tank you can move your betta into if things start getting ugly.
Again, doubly so since you’re doing this for an aquarium that’s already small.
Introducing Your Betta Last
One common bit of advice for increasing the chances that your betta will get along with the other fish you add to its aquarium is to make your betta the last fish you add to the tank.
The logic behind this is that anything that’s already there when it gets added is just part of its territory, rather than an invader that’s threatening its space.
If you already have your betta in its tank, you can try this:
- Get a small aquarium or fish bowl to move your betta into.
- After you’ve moved your betta out of it’s aquarium into the bowl, rearrange the setup in its old tank. Add/remove decorations and move things around so that it looks different.
- Introduce your betta’s new tank mates into the aquarium.
- Once they’ve had some time to settle down, move your betta back into the aquarium. It will look new to the betta at this point, so it will be like you added your betta last to a new setup.
In my experience this has worked out at least to some degree; though, I can’t say that it works perfectly every time.
There are those that say it’s a myth, but they don’t typically argue that it doesn’t work, just that you can add tank mates successfully without doing it if you’re careful enough. I agree – you can – but this may increase the chances of success a bit more.
It’ll just be up to you to decide whether it’s worth the effort.
Adding Hiding Spots
Since the tank is small and the fish don’t have a lot of room to get away in, you’ll want to add plenty of hides to your aquarium.
If you decide to go for smaller, nano fish, you can add some smaller hides that the betta would have trouble getting into. (In addition to larger ones for your betta.)
Otherwise, you can add plants – potentially some plants that grow thick like Java moss. These make good hiding spots for small fish as well.
This will make it easier for fish to get away if they’re being harassed.
Watching Water Quality
Adding more than just a betta to a 5 gallon aquarium could lead to ammonia spikes harming or killing your fish.
Because of this, you’re going to want to regularly test your water for ammonia, nitrite, and nitrates to make sure your aquarium water isn’t becoming toxic. You’ll also want to change 50% of your aquarium’s water at least once per week – more if testing indicates it’s necessary.
You can also plant fast growing plants – such as floating plants – in your aquarium to help absorb some of the nutrients that can be harmful to fish.
As long as you’re diligent about taking care of your tank’s water, there is no reason why this should keep you from adding your new fish to your aquarium.
Tank Mates You Do NOT Want To Put In With Your Betta Fish!
Now that we’ve discussed tank mates you might want to add with your betta, let’s discuss ones you absolutely do not want to add.
Betta should never be put in an aquarium with pea puffers, scarlet badis, cichlids, or other male bettas. These fish are aggressive, and it will result in either your betta or the other fish getting killed. Gourami are also a bad matchup, and a betta will attack sparkling gourami and kill them.
Here are a few bad matchups for betta:
- Pea Puffers
- Sparkling Gourami
- Scarlet Badis
- Most Barbs (known for nipping fins, which makes a bad matchup for a fish that’s 60% fin)
Hopefully this helps you know what fish can go in an aquarium with a betta safely and which ones to avoid. Good luck with your aquarium!
(Also, please upgrade to at least a 10 gallon aquarium – you’ll be doing yourself a huge favor.)