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How Many Goldfish in a 5 Gallon Tank? (Read This First!)

Goldfish and 5 gallon tanks are the most popular choices for beginner fish keepers. 5-gallon tanks look pretty standard in size and manageable.

But how many goldfish can live there? And what size goldfish can fit in the tank size. Here is a detailed guide about keeping goldfish in a 5 gallon tank.

How many goldfish in a 5 gallon tank?

About 3-4 small-sized (under 2 inches) goldfish will fit in a 5-gallon tank for a few years. If you keep two small goldfish, you can keep them for more months. But keeping goldfish in a 5-gallon tank is not a long-term thing but still manageable with proper maintenance.

You may hear that goldfish need a large tank everywhere, and smaller tanks are not suitable for them. Yes, that is so true, but what if you have no choice or a tight budget for a goldfish tank? Follow our guide to get a clear understanding.

Firstly, Goldfish needs a lot of oxygen as they have a bulky body. But the oxygen level will drop fast if you have a smaller tank. The fish will suffocate and swim at the top layer of the water.

And then, goldfish eat tons of food, and sometimes it seems like they produce more waste than they consume. The fish waste reduces the water quality faster if the water volume is only 5 gallons.

As the water quality will drop frequently, you will have to change the water more than a bigger tank. And if you delay changing the water for long, the waste will produce ammonia and other harmful objects that will reduce the lifespan of your fish so quickly.

For those reasons, a small 5-gallon tank is not ideal for goldfish. But wait, there is a way to keep them in a five-gallon tank. Let me explain how.

Get the 2-3 most petite sizes of goldfish you can find in the market. You should get 1.5-inch goldfish easily. 2 to 4 baby goldfish will easily fit in a five-gallon tank until they grow up. Set a sound filter with your aquarium and change 40-50% of the water every week.

You can go with 5-gallon tanks for 2-3 years by taking those steps. And by then, we hope you can manage a bigger tank for them for a comfortable life.

However, there are different types of goldfish, and some fish have special requirements. Check out if those fish can fit in a 5-gallon tank.

Common goldfish:

If you choose a 5-gallon tank for goldfish, small-sized common single tail goldfish will be suitable for you. Those goldfish are specially developed for mid-sized tanks and grow slightly slower than other goldfish.

Fancy goldfish:

Don’t go for fancy goldfish with such a small tank. Fancy goldfish grow very fast and need at least 20 gallons of water per fish once they are adults. Those goldfish are very expensive also. So that is the last thing you want to do.

Oranda goldfish:

Oranda goldfish is one of the most beautiful goldfish strains, and they can grow up to12 inches, so, as you can guess, they’re not suitable for a 5-gallon tank.

Black Moor goldfish:

As the name suggests, those goldfish are black and one of the popular strains of fancy guppies. A 5-gallon tank is not suitable for them.

Can goldfish live in a small tank?

Adult goldfish cannot live in a small tank. They need plenty of space, freshwater, and quality food to lead a healthy life. Let’s discuss why keeping them in a small tank is not suitable.

Goldfish are large:

Most goldfish can grow over 10 inches, and the fancy ones can grow even more. You may have heard the one-inch rule for fish in different places. The rule states that every one inch of fish needs one gallon of water.

It is true for many fishes, but that does not apply to the goldfish. They need about 20-gallon water to live. Keep reading for the explanation.

Growth inhibiting hormone:

Goldfish release growth-inhibiting hormone that causes a stunning growth rate. The hormone stays in a greater concentration in a smaller tank than a bigger tank. The hormone concentration reduces when you change the water regularly.

Waste producers:

Goldfish produce a large amount of waste, and that causes poor water quality. If you have a small tank, you will have to change the water frequently to keep the water fresh.

However, it is easier to maintain small tanks easily. But believe me, it becomes pretty frustrating when you have to do it frequently.

Is a 5 gallon tank big enough or good for a goldfish?

A five-gallon tank is not suitable enough for a goldfish. Even if you want to keep only one adult goldfish, you need a 15-gallon tank.

But as we mentioned earlier, a five-gallon tank can inhabit a few baby goldfish for a couple of years. But after then, the fish will get stunned and live in misery.

If you are confident that you can maintain the fish consistent enough and have enough time for that, go for it. If your fish are growing big and you cannot get a bigger tank for them, give them away to someone who has room in his tank and is willing to adopt.

How many comet goldfish can live in a 5 gallon tank?

None. The minimum tank size for comet goldfish is 50 gallons. Comet goldfish shines in small freshwater ponds and need a considerable space to live freely. So if you have a 5 gallon tank, don’t keep comet. Comet is also used for outdoor feeder fish.

Instead, keep small goldfish strains if you have a five-gallon tank. If you want to make a permanent five-gallon tank keep other small fish like guppies. These sized tanks are ideal for guppies and bettas.

Can 2 goldfish live in a 5 gallon tank?

Yes, two young-sized goldfish can live in a five-gallon tank for 1.5 to 2 years. Goldfish will outsize the tank and create unhealthy living conditions by that time.

When you notice your goldfish is not growing for a long time, a shortage of space can be a reason. A goldfish should live at least 15 years, but they don’t even make it to five years due to people’s carelessness.

How long can a goldfish live in a 5 gallon tank?

Small goldfish can live about two years in a 5 gallon tank. If you have 3-4 inches sized goldfish, they can live in a small tank for two years with proper care.

However, the goldfish can stop growing even before reaching the two-year mark without proper care like routine water change and quality food.

What size tanks do goldfish need?

So, if 5-gallon is not ideal for goldfish, what is the perfect and minimum size of a goldfish?

Minimum tank size:

20-gallon tanks are the minimum tank size for a permanent goldfish tank, although you can keep only two fish in a 20-gallon tank. If you own any smaller tank, the fish will struggle to live there and not reach the average lifespan.

Best tank size:

30-gallon tanks are the best size for a pair of goldfish. You will need to add 10 gallons to add another fish. For fancy guppies, 40 to 50-gallon tanks are required.

Can a goldfish live alone? How long can it live alone?

Yes, a goldfish can live alone and live to their average lifespan in a suitable condition. But should we keep goldfish alone in a tank forever? Well, it is better than stocking two in a small place.

Goldfish live happily with other tank mates. But we don’t exactly know if they feel lonely. Like all animals, all goldfish have different habits and preferences. Some may have no problem living alone.

Most of us keep fish for love, so I think we don’t need to build logic to keep them alone. Just get your pet a partner when you get a chance. Until that, you can spend time with him to tame and keep him happy.

What fish can live with goldfish in a 5 gallon tank?

Just keep some snails. Five gallons is already tiny for the goldfish, so do not add any other fish in that small space. Snails will not take any swimming space and help by eating the wasted food and algae.

However, the snails’ population can grow very fast if you overfeed them, limit the food availability and remove some snails when they become abundant.

Final thoughts

2-3 small-sized goldfish can live in a 5-gallon tank for a couple of years. After that, you will have to find a larger home for them. Fishkeeping is not a hobby once you get involved. It is a duty which you should never neglect, as some lives depend on you, and they can’t talk.