There are a lot of bad tanks available on the market. I saw one not too long ago that was only a half gallon to begin with but was divided up into two separate areas for two betta to live in.
A 3 gallon tank is a lot better than those, but is it actually good for a betta?
A long finned betta can live in a 3 gallon tank without much issue as long as you keep up with regular water changes and don’t overfeed. Short finned betta need more space. A long finned betta should still ideally be in at least a 5 gallon aquarium.
Let’s talk about the types of betta that work better for 3 gallon aquariums.
Is a 3 Gallon Aquarium Big Enough for a Betta?
The absolute minimum tank size I would ever keep a betta in is 2 gallons. A 5 or 10 gallon aquarium is preferable. Larger tanks reduce maintenance and maintain good water quality more easily.
Where do 3 gallon tanks fit in this range? It depends on the type of tank, to be honest. While I would recommend going up the extra few gallons to a 5 gallon tank (which may save you money if you get it at the petco doller-a-gallon sale), some 3 gallon tanks are better than others.
In general, though, you can safely keep a long-finned male betta in a 3 gallon tank safely as long as it’s the right shape. As I mentioned earlier, you do have to keep up on your weekly water changes to make sure ammonia doesn’t build up too much.
Ammonia building up in your aquarium water can be fatal to fish, so if you’re going to keep a betta in an aquarium this small, you want to make sure you’re keeping the environment healthy.
Adding some plants or moss balls can help but is not a substitute for water changes in this sized tank.
Plus, with the slow flow filters need to have for betta to be happy, changing your water regularly is the key to preventing hair algae taking over your tank.
Let’s talk about which 3 gallon tanks are and aren’t okay for bettas.
Tall 3-Gallon Tanks
For example, I would recommend staying away from the tall, round 3 gallon tanks. What little space they provide is in the wrong direction. Vertical space is much less useful for most types of fish than horizontal space is.
These round tanks may be good for stacking with fake plants and keeping cherry shrimp in, since they can use the space more effectively, but I wouldn’t keep any type of fish in one.
The tall, hex shaped tanks fall into this category as well.
3-Gallon Fish Bowls
The round-ish fish bowl type setups are a bit better, but not much. While they do give some more horizontal space where it’s necessary, it’s going to be hard to get any sort of filter into them, and it is also going to be hard to clean.
In the long run, this is going to lead to a less healthy setup for your betta.
Cube Style Tanks
Cube shaped tanks are starting to get a little better for a betta than the other types of tanks. They’re easy to clean, can fit a filter with little issue, and generally provide the best level of horizontal swimming room of the tanks we’ve discussed so far.
They’re not the best shape of tank, but they’re okay. If you absolutely couldn’t get anything bigger than a 3 gallon tank and already had a betta (or you have a betta in a tiny tank and want to upgrade it), I’d be okay with keeping your betta here.
If you can go for the next type of tank, however, it would be even better.
Rectangular Fish Tanks
The best type of 3 gallon fish tank are the ones that are wider than they are deep or tall. This puts most of the useable space the tank has into length that your betta can use to swim back and forth in.
Top fin makes a 3 gallon tank this shape, and I’m sure other brands do as well. If you must get a 3 gallon, this is the type of 3 gallon tank to get.
Again, I should stress that plakats and female betta shouldn’t be kept in any sort of 3 gallon tank. (Or anything smaller than a 10 gallon, ideally.) This is for long finned (male) betta only.
The short finned varieties mentioned above are more active and thus should be given more space.
How Many Betta Can Live in a 3 Gallon Aquarium?
Only 1 betta should ever be put in a 3 gallon aquarium. I would avoid using any dividers or other gadgets you might find to divide a 3 gallon aquarium into smaller areas for multiple betta.
The tanks just aren’t big enough, and it’s likely to cause stress or spread diseases. (And especially never put multiple betta in an undivided tank this small.)
How Many Female Betta Can Live in a 3 Gallon Aquarium?
You shouldn’t put any female betta in a 3 gallon aquarium. A landscape oriented 5 gallon tank is the bare minimum they should be kept in (same for plakats), and 10 gallons is ideal.
They just are too active for such a small tank. Give them the space they need to live comfortably in.
Long finned betta (that is to say male ones) aren’t as strong of swimmers as their short finned counterparts, so smaller tanks aren’t as hard on them.
Can You Keep Any Fish With a Betta in a 3 Gallon Tank?
I would avoid putting any tank mates (fish or otherwise) in with a betta in a tank this small. If you go up to 5 gallon tanks, there are a few options, but even then not that many.
The only ones that might be able to work would be pond/bladder snails and ramshorn snails. They’re super small and reproduce by themselves, so it’s not as big a deal if a few get bullied or eaten.
They’ll also help break down any food that slips past your betta and makes it to the bottom of the aquarium.
3 Gallon tanks are hit or miss. A betta can live a full life in a 3 gallon rectangular aquarium. The weird shaped tall ones, on the other hand, are generally bad ideas.
What’s common across all of them, however, is that a 5 gallon tank is almost always a better idea if you can get one.