Can Hoplo Catfish and Goldfish Live Together?

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You love the hoplo catfish, and you also love the goldfish, but you never thought about pairing them together. I know the feeling because your situation resonates with many other aquarists, and the internet is witness to that.

So, today we will discuss the unlikely marriage between the hoplo catfish and the notorious goldfish to see what we can learn.

Can you house them together, and if so, what should you know about their relationship? Let’s see.

Do Hoplo Catfish and Goldfish Get Along?

Yes, they do. Both hoplo catfish and goldfish are peaceful and social animals that display little-to-no territorial or aggressive behavior. This being said, you do need to consider some aspects that could make or break their relationship.

For one, the hoplo catfish is a bottom dweller, which is expected from a catfish. So, this fish spends most of its life roaming around the substrate on a constant lookout for food and shelter.

The problem is that goldfish also spend a lot of time near the substrate, mostly for feeding purposes.

So, it’s likely that the 2 will cross paths regularly. This isn’t a problem for the most part, but you need to make sure that they have sufficient space. And that the hoplo catfish has some hiding places available in case it needs refuge.

Also, keep in mind that goldfish are notorious eaters. They lack that little mechanism in the brain that informs them when enough is enough.

So, expect them to eat as much food as they can find. This can cause the hoplo to starve, so you need to balance things nicely for your fish in terms of feeding opportunities.

Keeping Hoplo Catfish with Goldfish

Now that you know that the 2 species are compatible let’s see how you can create a compatible and nourishing environment for both of them.

There are several pointers to consider here:

Choosing the Right Tank Size

The situation is clear with the hoplo catfish. This species grows up to 5-6 inches, making for a medium-sized fish that doesn’t need too much space. You only require approximately 10-15 gallons for one hoplo catfish.

The situation changes radically with the introduction of the goldfish. This is a peculiar species because goldfish are notorious for reaching impressive sizes, although starting very small.

These fish can reach 16 inches or more in the wild. Interestingly enough, they remain smaller in captivity, but this varies a lot.

Some species remain as small as 1-2 inches, while others can reach 6. So, you may need 20-30-40 or 50+ gallons, depending on the goldfish species and the fish’s growth potential.

Generally speaking, the size of your goldfish is influenced by the available space; so, the more space the goldfish has, the larger it will grow to a point. I recommend at least 30 gallons for your goldfish, making up for around 40-50 gallons for your hoplo-goldfish pair.

Getting the Right Aquarium Substrate

Go with sand. Sand looks great, outclassed only by gravel, and it is perfect for catfish and goldfish alike.

Catfish, especially, require a fine and soft substrate for burying purposes. Catfish are known burrowers, and you need a fine substrate to prevent skin lesions that can infect fast in the bacteria-filled tank water.

Goldfish can also use a finer and softer substrate, given that they, too, dig around for meal opportunities.

When it comes to sand, though, keep the following specifications in the back of your mind:

  • This is an inert substrate – The notion of inert refers to being devoid of any nutrients. So, sand is suboptimal for live plants, unless you use root tablets for adequate fertilization.
  • The dangers of anaerobic pockets – Anaerobic pockets form due to the sand’s compaction and particle size. In short, the sand particles are so small and compacted that they prevent water from circulating through the substrate. This will lead to the formation of anaerobic pockets, which are ammonia-filled bubbles that create a deadly environmental hazard. Substrate stirring and vacuuming is necessary to prevent them.
  • Filtration hazard – You don’t want your sand stirred up too violently, too often. The small, fine particles will get sucked into the filtration system and overburden or clog the filter. This can be easier said than achieved when housing substrate diggers whose sole job is to stir the substrate.

Fortunately, there are fixes to consider which make sand great for your hoplo/goldfish aquarium.

Setting the Right Temperature

The hoplo catfish requires temperatures around 64-82 F which is probably the largest temperature range in any fish species.

This allows you to house the hoplo with virtually any other species, so long as they’re peaceful and match up greatly with your catfish in general.

Goldfish are considered cold-water fish that require sub 70 F temperatures. So, you shouldn’t have problems finding the goldilocks zone for the 2.

Feeding a Balanced Diet

Both the hoplo catfish and goldfish rank as omnivorous, opportunistic eaters, but their diets vary in many aspects. For one, hoplo catfish consume more animal protein than goldfish.

Their diet consists mainly of small crustaceans, insect larvae, bloodworms, and other small creatures swimming in their habitat.

They can also use various pellets and flakes, depending on their eating preferences. Hoplo catfish are somewhat pretentious about their food, so not all fish will enjoy the same foods.

Goldfish, on the other hand, prefer more plant matter than animal-based foods. Their diet should consist of 30-35% animal protein, 5% fat, and plant matter and veggies for the remaining percentage points.

Two things I should point out here:

  • The goldfish’s unmatched appetite – Few fish eat more than the goldfish. These fish are widely known for their insatiable appetites, leading them to consume anything they can find. If it exists, your goldfish will eat it. This can cause some problems in a community setting, given that goldfish have no intention of sharing their food with anyone.
  • The hoplo’s scavenging behavior – Hoplo catfish, don’t need that much food compared to the goldfish because the fish will consume any food residues reaching the substrate anyway. So, you need to adjust the fish’s diet and meal plan properly, depending on its appetite and feeding tendencies.

Changing Water Regularly

This is a must in any goldfish tank due to the fish’s infamous pooping capabilities. Goldfish are notoriously messy, often producing more poop than the filtration system can handle.

While goldfish can manage some ammonia and nitrite increase, you can’t say the same about the hoplo catfish.

At a minimum, you should perform weekly water changes of 20-25% of the total water volume. This is necessary to dilute any harmful chemicals in the water and reoxygenate the ecosystem properly.

Pair the water changes with some good maintenance work and substrate vacuuming to remove dead matter, decaying food residues, and excessive fish waste.

A clean and healthy aquatic environment is essential for your fish’s overall quality of life.


Hoplo catfish and goldfish are made for one another. They have similar temperaments and personalities and share the same environmental requirements.

Despite that, they do have their differences which I hope this article did a great job at highlighting and evening them out.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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