What is the correct size of tank for a betta and some tank mates?


Hi, I'm thinking about making a tank for a betta with an old 8-gallon tank I have at home but am confused about the optimal size tank for a betta. Some sites say that 5 gallons is the minimum and 10 gallons is the max and some like this forum's Knowlege library says 10 gallons and no smaller and some even say 2 gallons is enough. So which is it in your opinion, Over 10 or under 10?

Plus I plan to give my betta some tank mates cause I heard from a few places that the right tank mates can make your betta happy but also say that a 5-10 gallon tank is fine for a betta and tank mates.

I don't really want the tank to be too small for the boy and some of his mates but I'm receiving mixed information on the ideal size of a tank.

also i heard that the tank should not be too deep and mine is 35 cm deep and 30 cm wide and long, is that too deep?

I'm planning maybe 5-6 neon tetras or similar and a betta to go in the tank.

Ps I'm new to this forum and I really don't mind getting a new tank if the one i have is not ideal.
Best Answer - View Dippiedee's answer

Donovan Jones

It's too small of a footprint tbh. I'd go for a regular 10 gallon personally, because I dont like keeping fish in anything less. Then you could add a school of 8 pygmy corydoras, green neons, or ember tetras, depending on your bettas temperament of course
Edit...it may work for a betta and some sort of shrimp and snails but not a schooling fish.


IMO keeping a fish in anything smaller than a 5 gallon is cruel; fish are living animals. You wouldnt buy a dog and keep it in a crate its whole life for example. 5 gallons is the absolute minimum but that's too small for the betta to share the space with tank mates. I would get a 10 gallon; my betta is in a 10 gallon with 5 harlequin rasboras.


First, I just want to commend you for seeking clarification to your questions.

A 5 gallon IMO is the minimum and there is technically no maximum if the tank set up correctly (enough live plants, hiding spots etc) so the betta feels safe. It's just more "territory" and area to patrol and explore. It's important the tank isn't bare, and has an abundance of safe decorations and/or plants because bettas do not like feeling exposed or out in the open. Contrary to popular belief, you'll actually see your fish more if you have enough hiding places because they will feel safer exploring the tank knowing they can easily hide.

Bettas are a solitary species that is VERY territorial and the vast majority will not tolerate tankmates at all. Tankmates do not positively affect the happiness of a betta, I cannot stress this enough. Depending on the personality of the betta the tankmates can actually cause stress which can lead to health problems. If your fish is as aggressive as the "average" betta (AKA the vast majority) it will try to kill it's tankmates.

As already mentioned by others, the tank dimensions you have are not big enough for a school of neons, they are very active fish who need large schools and a 20 gallon minimum to thrive.


I believe that if you have a 10 gallon- just use it for a betta. Don't add any fish other than the betta. I believe that keeping bettas in anything smaller than 5 gallons is abuse. I saw a recent post (on FishLore) about someone keeping 2 bettas in vases. Complete fish abuse. I believe that a 5 gallon is the minimum.


The bigger the better IMO as they are naturally territorial.. but I have a beautiful betta boy with a bristlenose and 6 harlequins and heaps of snails in a 130L (30 gal?) Planted tank and everyone is getting along great :) he's even seemed to really bond with the pleco, they're always hanging out together and he swishes his fins against her swimming above her it's so cute... the betta's natural habitat has many other species of fish which they live with peacefully and they are so intelligent and curious, I think the other fish give them much needed enrichment and stimulation.



I think a 15 gallon is a good tank. Look at it this way. If you are going by the inch per gallon rule that is not accurate, bettas without the tail are about 2.5 inches. With the tail let's say about an inch more. You are already more than the 3 inch. You are 0.5 over. Your betta also wants swimming room. They have amazing personalities. Do not go by the inch per gallon rule and like I said it is not accurate. I have my betta in a 5.5 gallon. (setting up a 20 gal community planted tank w/ a betta and I am really excited) and the betta wants swimming room too. So, 5 gallons is the minimum and you want 5 gallons of personal space for your betta. If you go with a 10 gallon you will only have 5 gallons of room for tank mates. The smaller the tank, the quicker things can go sideways.


It all depends on the Betta you are planning to get. There are the big finned ones that don't move as much, and there is the more active short finned variety.
I started the male Betta in a five gallon tank and for some reason he just looked crammed. He is now in a 12gl tank and the ratio fish to tank looks just more natural.
Tankmates did not work out, just too much stress, so he is solo in the tank. Even the Nerite always had to watch her antennas, and finally said 'enough is enough' and skyed out of the tank.
The female Betta is on the other hand worked out great in the 5gl tank.
So visualize what you want in a Betta, then plan and work from there.
Top Bottom