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What Fish Are Good for a 1.5 Gallon Tank?

I saw this question posted online and some of the answers offered I don’t agree with. One article I read was suggesting suitable fish for a 1 gallon tank, so even smaller. One of their suggestions was goldfish. In my experience, I don’t find that to be a good idea at all.

What fish are good for a 1.5 gallon tank? The right fish to select for a 1.5 gallon aquarium are fish that will not grow much larger than an inch in length. Shrimp, Neon Tetra’s, Platy’s, Pygmy Cory’s, Guppy’s and Kuhli Loaches are good selections.  The fish best suited for such a small tank would preferably not be schooling fish, however some schooling fish can be in smaller groups.

Some critical thinking aquarium hobbyists will go as far as saying you should only have snails and shrimp in a tank that small. Unfortunately, I don’t agree with them either. This is good news for you because now you get the advice of someone who has been in the hobby for a few decades!  I feel you should have some very small fish species in a very small aquarium and provide them a healthy environment and long life.

That being said, I do agree with bigger is better especially with aquariums. However, if you do really want such a small tank, what are your options? Keep reading to find out.

Can Any Fish Live in a 1 Gallon Tank? [What You Need to Consider]

Technically, yes and no at some point, whether it’s when the fish is young and very small it could live in such a small tank. It doesn’t mean you should do it, however. Betta have shown that they can survive in extremely small containers at pet stores yet they shouldn’t be in those small containers. Goldfish are another one. People grow up being taught that Goldfish live in fish bowls.

Again, they could for a while, if the water was taken care of then eventually the fish would outgrow its bowl and require an aquarium much larger. The key to success is making sure the tanks water is cycled, filtered and changed on a regular basis. With such a small set-up, water changes will be necessary every week most definitely.

Over the years, views are starting to change on what constitutes the appropriate sized tank and care required for a specific species of fish. Fifty years ago or more, there just wasn’t the knowledge base and vast experience that there is today. So many people have aquariums and not just one or two, but many at one time. The hobby is extremely popular all over the world. With this massive interest in aquarium fish, we are learning so much about each fish.

Below I have selected some fish off the top of my head that I would keep in a 1.5 (or 1 gallon) tank if I was setting up a new one. I will give you a brief explanation as to why I would pick these fish. Hmmm, maybe I need a small tank in the office, after all!

Something to note, I am suggesting fish below but not suggesting you purchase everything below for a 1.5 tank. Each fish I list below should be in the small tank with its own species and no other fish. So just Cory’s or just Neon’s, etc.

Will Pygmy Cory’s Survive in a 1.5 Gallon Tank?

Every tank needs some bottom dwellers and the best fish I can think of for such a small tank are Pygmy Cory’s.

Pygmy Cory’s grow to just over an inch in length. As with all Cory catfish, a school is always recommended. They just seem to thrive better when there are 4 or 5 living together.

For a 1.5 gallon tank you could get away with 3 Pygmy Cory’s. I have seen Cory’s live well alone so having 5 or 6 in a school is probably not necessary. That’s my opinion. I would have more of them in a larger tank though. As a matter of fact, I have a 10 gallon aquarium I am slowly adding fish to and plan on purchasing 5 to 6 Pygmy Cory’s.

These active little catfish will be a treat to watch in a small tank.

Will Neon Tetra’s Survive in a 1.5 Gallon Tank?

Now the critical aquarium hobbyists will try jumping all over this one. It is a general rule of thumb that Neon Tetra’s should be kept in schools of 5 or more fish. If you go by the other rule of thumb of an inch of fish per gallon of water (this must have been made up with beginners in mind) you can see the dilemma. Neon’s grow up to 1.5 inches, if you are lucky enough to have them live that long.

The calculation here would be a school of adult Neon Tetra’s measuring 1.5 inches each totaling 7.5 inches when converted to the proper amount of gallons per inch of fish would be 7.5 gallons. So you are short about 6 gallons. Never fear though because you are going to purchase a maximum of three very small tetras which will do just fine.

Will Platy’s Survive in a 1.5 Gallon Tank?

I would consider putting a few Platy fish in the 1.5 gallon tank. They would show nicely especially with some contrasting substrate and maybe background for the tank.

Platy’s are a hardy species of aquarium fish that will do just fine in a small tank.

Guppy’s are a Fine Option for a 1.5 Gallon Aquarium

Guppy’s are such a treat to watch. Their fins are bright and colorful displaying different patterns thanks to hobbyists into playing mad scientist and seeing what kind of Guppy creation they can come up with when breeding the fish.

One thing you should be aware  if you go this route is that Guppy’s are like the rabbits of aquariums. They are notorious for being easy to breed. Sometimes without the owner knowing until Frye are spotted.

How many guppies can you put in a 1.5 gallon tank? I would be comfortable recommending 3 or 4 fish easily.

Will Kuhli Loaches Survive in a 1.5 Gallon Tank?

Kuhli loaches are very interesting creatures. They remind me of snakes and worms all in one! Loaches burrow themselves into the substrate so you won’t see them all the time. Some loaches grow quite large and this size tank wouldn’t be large enough. Kuhli’s should have no problem, especially when they are young.

If you do opt for a loach or two in this case, you could get a couple of small fish as well. I would stay away from having loaches and cory’s in the same tank as they are both bottom dwellers and the area is so small it would be crowded and not ideal.

There you have some suggestions for stocking your aquarium. I think it would be important to also suggest a couple of fish I wouldn’t recommend for such a small aquarium.

Fish I Wouldn’t Recommend for a 1.5 Gallon Aquarium

I already mentioned Betta fish at the start of this article. Even though a Betta could survive quite well in a 1.5 gallon tank, it would do even better in a 10 gallon setup. I have seen Bettas in 10 gallon tanks and they have more room to swim and just seem to be so much happier and healthier.

Another fish I would not recommend for such a small tank is a Goldfish. As mentioned previously, just because the fish is associated with fish bowls doesn’t mean they really should be kept in one. Decades ago, without knowing any better, Goldfish were promoted as being the perfect selection for a fish bowl. They were marketed this way. A cold water fish in a cold bowl of water only seemed to make sense right?

That’s where this falls apart for me. Goldfish need larger tanks plain and simple. They get large and need much more room to swim around in the hectic way that they swim. They are a messy fish with huge poops that should be in bigger tanks. That’s my opinion.

Can I Put my Fish in the Tank Right Away?

Now that you know what you are buying, can you just go and put the fish in the water right away?

No, not unless the water has been cycled and is the appropriate temperature for the fish. I have an excellent article where I explain what cycling your tank means and how to go about doing it. You will save yourself some grief by learning this and also the loves of fish that will die much easier if the tank has not been cycled yet. Check out my article here. Aquarium nitrogen cycle.

How Do You Add Fish to a Tank?

When adding your fish, make sure to float the bag you bring them home in on the top of the tank for 15 to 20 minutes. This syncs up the temp of the tank and the water in the bag. This means less chance of shocking the fish.

When ready to open the bag, let a bit of the aquariums water into the bag so the water mixes. Slowly tip the fish out of the bag into the aquarium. Make sure the lights are turned off during this process. Do not feed the fish until the next day. I have a thorough article on introducing new fish to an aquarium. Make sure to check it out.

If you are still looking for a tank I have a recommended aquariums page or to make it even easier I am adding a link to Amazon to a really nice 1.5 gallon aquarium I would recommend. The Amazon tank I have linked to is a 1.6 gallon aquarium however once you put substrate in it there will only be about 1.5 gallons or less of water. 


There you have it, now you have some great options to stock in a very small 1.5 gallon aquarium.

The most important thing you can do for your fish, regardless of the size of the tank, is to ensure you do regular maintenance on the water. Learning and understanding what makes water safe for fish is extremely important for the survival of your pet.

Think of it this way, if we had to worry about breathing in poison every day 24 hours a day and the only way the air was clean was if someone else purified it, then we would be in the same situation our fish are in. I hope that made sense. I am very passionate about the survival of our pet fish. They deserve it.

Good luck with setting up, stocking and then enjoying your tank.

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