Can Guppies and Hatchetfish Live Together?

Disclosure: When you purchase something through my affiliate links, I earn a small commission. As an Amazon Associate we earn from qualifying purchases. read more

Community tanks are extremely popular among aquarists for good reasons. They tend to be larger and offer more variety in terms of fish and decorative settings. Single-species aquariums can get boring after a while.

The problem with community tanks, however, is that they are prone an issue that doesn’t exist with species-only tanks: species compatibility. Instead of setting up the aquatic habitat to accommodate one species, you now need to accommodate 2 or more. This can cause some noticeable difficulties along the way, which will grow exponentially with each new species you add to the mix.

Today, we will discuss mixing the notorious guppies with an equally small species, the hatchetfish. Are they compatible and, if not, why not?

Let’s assess the 2 and see what we can find!

Do Guppies and Hatchetfish Get Along?

This is a tricky one, and checking various articles on the topic will highlight precisely that. Despite their differences, some will claim that guppies and hatchetfish aren’t really compatible, while others recommend them as tank mates. This article will fall in the latter category, and I will explain why.

Here are the key differences between the 2 species that don’t really prevent them from cohabiting in the same environment:

– Omnivorous vs Carnivorous

Guppies are omnivorous, while hatchetfish are carnivorous. This will immediately raise an alarm signal since you’re not supposed to pair omnivorous and carnivorous fish species. The de-escalation factor here is the fish’s size.

The hatchetfish won’t grow more than 1 to 2.5 inches at most. The largest species, the giant hatchetfish, will only add 1 inch to the highest value, measuring up to 3.5 inches. So, a hatchetfish won’t grow larger than a guppy, which means they won’t see guppies as food.

– Aggression

The official recommendation is to only pair species that prefer different aquarium areas. This will minimize the interactions between the 2, keeping the risks of inter-species aggression at a minimum. However, guppies and hatchetfish share the same swimming space since guppies are middle-to-top dwellers while hatchetfish are top dwellers.

This could spell problems if it weren’t for the hatchetfish’s calm and friendly demeanor. Guppies are way more active than hatchetfish, who spend most of their time swimming gently in place, conserving energy.

This is their typical behavior in the wild, allowing the fish only to use its energy when detecting potential prey, at which point they will zoom towards their target at full speed. Other than that, they don’t move much. And guppies aren’t as active as to cause hatchetfish discomfort, knowing that the latter don’t fare well in the company of hyperactive fish.

– Sensitive Fish

Hatchetfish are rather sensitive to changes in their environmental parameters. They are particularly sensitive to ammonia and nitrites, which may weaken their immune system and cause them to fall sick. This may seem like a big issue, seeing how keeping hatchetfish with a shoal of several guppies in a rather small tank can create problems.

There’s a reason why hatchetfish are not quite the beginner-friendly species that you’ve been looking for. But there are ways to effectively circumvent the issue. First, consider investing in a larger tank. I’m talking larger enough to accommodate 10 to 12 fish, hatchetfish and guppies included. That’s considering that hatchetfish also live in shoals of at least 5-6 members.

There should also be enough space for plants and various decorations since hatchetfish are rather shy and like to have their own safe spaces to retreat to. Approach the situation from a smart angle, and there’s no reason why you can’t accommodate both species.

Keeping Guppies with Hatchetfish

Now that you’ve learned that guppies and hatchetfish can live together let’s talk about their system requirements.

– Tank Size

The aquarium’s size depends on how many fish of each species you plan on keeping. Guppies and hatchetfish both prefer to live in shoals, with 6 being the minimum recommended fish number for each species. Guppies need around 2 gallons of water per fish, and the same applies to hatchetfish.

You can probably accommodate both groups in a 30-gallon tank, but I would recommend a larger one, at least 40-gallons large. That’s because the tank also needs room for equipment, like heater and a filtering system, and various decorations like plants, caves, and rocks.

The primary goal should be to craft a natural-looking environment for both species to enjoy. Especially when considering that hatchetfish and guppies love vegetation and prefer a richer environment to explore and hide when necessary.

– Water Temperature

Fortunately, both species thrive in similar temperature conditions. Set your water temperature at a value between 72 to 82 F, and your fish will thrive. The key is to prevent massive or frequent temperature fluctuations, which may cause your fish discomfort and even health issues along the way.

Both guppies and hatchetfish are sensitive to sudden or frequent changes in their water parameters, temperature included. Consider a reliable heating system, especially if the room temperature isn’t stable throughout the day.

– Diet and Feeding

Both guppies and hatchetfish consume their food at the water’s surface. This can lead to food competition, especially in small tanks, where the fish don’t have sufficient room at their disposal.

Guppies have an omnivorous diet and will consume a variety of foods like brine shrimp, algae, plants, flakes, bloodworms, mosquito larvae, etc. You can also feed them specialized fish food and vitamins to complement their diet if lacking vital nutrients.

The hatchetfish is carnivorous and will eat much of the food guppies also love. They also consume flakes and other store-bought food options if necessary but would prefer live food as a general rule. It’s also worthy of noting that hatchetfish love insects more than anything else.

This is why hatchetfish will spend most of their time at their water surface and why they have such well-developed thorax muscles and wing-life pectoral fins. They are extremely good jumpers, popping out of the water to catch insects in mid-flight.

Some species of hatchetfish, like marble hatchetfish, can jump up to 5 feet high, which is astounding, giving the fish’s petite size. So, you might want to keep your tank lid on at all times.

– Water Changes

This is where things get tricky, since hatchetfish are more sensitive to poor water conditions than guppies. Guppies will adapt to, let’s say, suboptimal water conditions, although they too require regular maintenance and a clean environment. Hatchetfish, on the other hand, are more sensitive to changes in the water chemistry.

Depending on how many hatchetfish you have, you may need to perform 2 water changes per week. Some suggest water changes of around 25% to 50% twice per week, but I think that’s way too high. Changing such a volume of water will dilute the essential minerals present in the fish’s habitat, potentially disrupting beneficial bacteria cultures.

If you need to perform 2 water changes per week, don’t go above 15%.

Hatchetfish’s specialized water requirements are one of the main reasons this species ranks as non-beginner-friendly.

– Number of Fish

How many fish you will have depends on how the environment is set up. I recommend at least 50 gallons of water for any decent community tank. This allows you to add several species of fish, depending on their size and numbers, and decorate the tank with plants, wood, aquatic rocks, and other elements.

When it comes to guppies and hatchetfish, you should have at least 6 of each. In theory, you should be fine with a 25-30-gallon tank. Both species are shoaling in nature, which means they tend to stick together and will feel the most comfortable in groups.

Just limit the number of males accordingly. Guppy males can become quite aggressive towards one another during feeding, mating, patrolling their territory, and simply existing in each other’s vicinity. The same goes for the hatchetfish.

Do Hatchetfish Eat Baby Guppies?

If there are any fish species that eat baby guppies, that has to be the hatchetfish. These tiny predators will view the guppy fry as easy meals. A group of 6 hatchetfish will eliminate everything small enough to fit their mouths and guppy fry all qualify for that.

The problem is even more prevalent when considering that newborn fry tend to gather at the water’s surface, which, coincidentally, is also the hatchetfish’s hunting ground. Adding a variety of floating, surface plants for the fry to hide in won’t help too much either. Hatchetfish also use these plants to rest and scan for their next meal swimming by.

If you want to breed guppies but you have a population of hatchetfish to worry about, consider investing in a breeding tank. Move the pregnant female into the breeding tank and move it back into the main tank once she’s done delivering all the fry. This will keep the female from eating the young, which is more common than you’d think.

The fry will grow uninhibited and will soon grow large enough to no longer rank as food for the hatchetfish. Given higher environmental temperatures and a protein and fat-rich diet, a 4-week period should be enough for the fry to grow to sizeable proportions.


Guppies and hatchetfish are different in temperament, water requirements, and diet, yet they can get along with each other. It takes some planning and monitoring to make sure everything clicks and that both species are comfortable and acceptant of each other.

Updated: February 8, 2022
Leave a Comment

Your email address will not be published. Required fields are marked *