Two Betta Fish in One Tank: Why You Need Two Tanks

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Two bettas should not share open water in one tank. The Wikipedia species overview says male bettas are highly territorial and frequently fight when kept together, and that female bettas can also become territorial toward each other in confined spaces. So the practical answer to “two betta fish in one tank” is one fish per tank, with two separate tanks side by side if you want two bettas. This guide lists five tanks from 5 to 10 gallons that fit that plan, starting with the Marineland Portrait 5 gallon kit, and explains why we leave out the small divided tanks sold for this purpose.

Who should pick which setup

• You want one betta: a tank of 5 gallons or more. This site’s rule is at least 5 gallons for a single betta, and we do not recommend bowls or any tank under 5 gallons.
• You want two bettas: buy two separate tanks of 5 gallons or more each. Do not share one tank between two males. The species overview describes male bettas as fighting when kept together, and it also says females can be territorial in confined spaces, so we do not suggest sharing water between two females in a small tank either.
• You want a betta plus other fish: the same overview says a betta housed with other fish needs at least 45 litres, about 12 US gallons (45 litres is 11.9 US gallons). None of the five tanks below is that large, so this guide does not pick a tank for tank mates. See our tank mates guide for a male betta before choosing the other fish, and plan on a tank of at least 12 gallons.
• You want a divided tank: be careful. The only divided kit considered here is a 3 gallon tank with a separator plate, which would leave each fish well under the minimum. We explain this below and do not link it.

The fit rule: footprint first, then gallons

Two tanks on one shelf or desk is a footprint question before it is a gallon question. The listings give each tank’s outside dimensions, and they differ more than the gallon figures suggest. Use the numbers below to decide what fits your furniture, and remember that the listed gallons are the maker’s capacity figure, not the water volume you will have once substrate and decor are in.

• Marineland Portrait 5 gallon: 9.99 x 9.67 x 17.2 inches. Small footprint, tall.
• Vimvins 5 gallon: 15.15 x 7.48 x 10.24 inches. Long and low.
• HYUVCX 5.3 gallon: 8.27 x 8.27 x 18.74 inches. Narrow and tall.
• YHDSYN 6 gallon: 19.5 x 8.4 x 8.4 inches. The longest of the 5 and 6 gallon tanks, and the shortest in height.
• Vimvins 10 gallon: 19.68 x 10.23 x 11.81 inches. Needs a sturdy surface; the listing gives its item weight as 18 pounds, before any water.

The five tanks

1. Marineland Portrait 5 gallon fish tank kit

• Tank volume: 5 gallons. Material: glass. Color: black.
• Size: 9.99 x 9.67 x 17.2 inches. Weight: 16 pounds.
• Includes: LED light, filtration and a filter cartridge; fits Marineland Rite-Size Z cartridges.

The listing describes rounded corners with a clear glass canopy for viewing from several angles, daylight and moonlight LED modes, hidden three-stage filtration, and a hinged light with a sliding canopy for access. Of the glass tanks, this one takes the least floor space for its volume, which is why it is the first pick when you need to fit two glass tanks side by side.

Limitation: it is tall for its footprint, so reaching decor at the bottom takes more effort, and the listing does not mention a heater. A betta tank needs one in most rooms, so plan to buy it separately. See the small betta heater guide for choices.

View the Marineland Portrait kit on Amazon (affiliate link)

2. Vimvins 5 gallon glass tank with filter, light and lid

• Tank volume: 5 gallons. Material: glass.
• Size: 15.15 x 7.48 x 10.24 inches. Weight: 3.18 kg.
• Includes: filter, light and lid; two-stage physical and biochemical filtration; dimmable LED with 3 modes.

The listing calls the filter ultra-quiet and the light dimmable with a one-touch switch. The long, low shape gives a wide surface and is easier to reach into than a tall tank. If you want two of these side by side, you need about 30 inches of shelf for the pair, measured from the 15.15 inch length in the listing.

Limitation: the listing does not state a heater or the filter’s flow rate, so you cannot tell from it how strong the water movement is. The special feature is listed as self-cleaning, but the listing gives no detail on what that means, so treat it as a marketing term and plan regular water changes.

View the Vimvins 5 gallon tank on Amazon (affiliate link)

3. HYUVCX 5.3 gallon starter kit

• Tank volume: 5.3 gallons. Materials: AS plastic, PET and polypropylene.
• Size: 8.27 x 8.27 x 18.74 inches. Weight: 1.7 kg.
• Includes: 3-color LED light, 3-mode filter, hydroponic basket, net, aquatic plant, shells, pebbles and coral.

This is the lightest of the group at 1.7 kg for the tank, and the listing says the semi-open top has a hydroponic planting basket, a storage groove and an oxygen hole. The filter is described as 30 dB or lower with three replaceable filter tips.

Limitation: a semi-open top is an opening, so a betta that jumps could leave through it. The listing does not discuss that. Several of the included decorations are described only by name, with no sizes given.

View the HYUVCX 5.3 gallon kit on Amazon (affiliate link)

4. YHDSYN 6 gallon starter kit

• Tank volume: 6 gallons. Material: AS plastic, PET and polypropylene.
• Size: 19.5 x 8.4 x 8.4 inches. Weight: 5.7 pounds.
• Includes: air pump, filter and light; four-layer hanging filter; 3-color LED with 9 dimming steps.

The listing is the only one in the group that names an air pump as an included part, and it describes extra filter media for beneficial bacteria. At 19.5 inches long it gives a betta the most horizontal swimming distance of the three smaller tanks.

Limitation: the listing also markets the tank for Cardinal Tetras, Zebra Danios and shrimp, which is general product copy, so check species compatibility with a betta separately before mixing anything. It lists a drainage hole as a feature but does not explain it, and it does not mention a lid.

View the YHDSYN 6 gallon kit on Amazon (affiliate link)

5. Vimvins 10 gallon glass tank with filter, light and lid

• Tank volume: 10 gallons (about 38 litres). Material: glass.
• Size: 19.68 x 10.23 x 11.81 inches. Weight: 18 pounds.
• Includes: filter, light and lid; 15W LED with 3 color modes.

Choose this one if you want a single betta in more space. It is not a tank-mate tank: 10 US gallons is about 38 litres, which is below the 45 litres the Wikipedia overview gives for a betta housed with other fish. The listing describes a two-stage filter and a lens-equipped 15W LED.

Limitation: a bigger tank means more water to heat and more weight on the shelf. A 10 gallon glass tank is not a desk item, and the listing does not mention a heater. For setup details, see the 10 gallon betta setup guide.

View the Vimvins 10 gallon tank on Amazon (affiliate link)

Why we do not recommend the divided 3 gallon kit

One listing, the iPriro 3 gallon tank, includes a separator plate and describes dividers and shields as suitable for hosting two bettas. The tank is 12.6 x 6.3 x 8.67 inches and holds 3 gallons. Divide that in two and each fish gets about a gallon and a half, which is well below the 5 gallon minimum this site sets for one betta, so we have not linked it. If you still want a divided setup, size it so each side meets the 5 gallon rule, which in practice means a much larger tank than any divided kit we found.

What to check before you buy

• Measure the shelf for the outside dimensions, not the gallons.
• Check the top. The Marineland listing states a glass canopy and both Vimvins listings state a lid. The HYUVCX top is semi-open, and the YHDSYN listing does not mention a lid.
• Check for a heater. None of the five listings states one, so plan to buy a heater separately for whichever tank you choose.
• Treat 5 gallons as the floor, not the target: if your budget and space allow 10 gallons, a larger tank is easier to keep stable.

FAQ

Can two male bettas share a tank?

No. The Wikipedia species overview says male bettas are highly territorial and frequently fight when kept together.

Can two female bettas share a tank?

The same overview says female bettas can also become territorial toward one another in confined spaces. This guide has no source on female groups, so it gives no recommendation for them.

Can a male and a female share a tank?

This guide does not cover pairing a male with a female. The species overview only warns about territorial behavior, so we do not recommend it.

How big a tank does one betta need?

This site recommends at least 5 gallons for a single betta. The overview says a betta housed with other fish needs at least 45 litres, about 12 US gallons.

Is a bigger footprint better than more height?

The listings do not answer this. They give dimensions only, so the choice comes down to what fits your furniture and which shape you can maintain.

Bottom line

If you want two bettas, buy two tanks. The Marineland Portrait 5 gallon is the glass tank that saves the most room (the HYUVCX is narrower still but is plastic), the Vimvins 5 gallon is easiest to reach into, and the YHDSYN 6 gallon is the longest of the 5 and 6 gallon tanks. The 10 gallon Vimvins is the largest tank here, but at about 38 litres it is below the 45 litre figure for a betta with tank mates, so no tank in this guide is recommended for that setup. Skip any kit that divides a small tank in half.