Glass Catfish 101: Tank Size, Diet, Breeding, Care & More!

When it comes to unique, slightly weird-looking freshwater fish, the Glass catfish easily comes to mind. This ghost-like apparition swimming around in your tank will undoubtedly catch everyone’s attention; you included.

So if that sounds right up your alley, then there is no clearer answer-the Glass catfish might just be your next aquatic pet. 

The table below gives a quick overview of the Glass Catfish profile:

Profile AttributeValue
Care DifficultyModerate
LifespanUp to 5 years
DietOmnivorous
Color(s)Translucent (may be iridescent)
TemperamentPeaceful/shy
Maximum Size2.6 inches
Minimum Tank Size5 gallons per glass catfish (20-30 gallons per school of 5)
Tank SetupHeavily planted
FamilySiluridae
CompatibilityCommunity fish

Below is our Glass Catfish care guide, continue reading to find out more about its Tank Mates, Breeding, Diet and more.

Overview

The Glass catfish (Kryptopterus vitreolus) is known by many names. Some call them the Ghost catfish, Phantom catfish, Glass Cat, and Asian Glass catfish of the Siluridae family. The scientific name itself is a combination of the Greek word Kryptos meaning ‘hidden’, and pterygio meaning ‘fin’. This pertains to their lack of a dorsal fin. While the species name vitreolus is from the Latin vitreus, meaning ‘glass’. Together, they construct ‘hidden fin’ and ‘glass’, which are perfect descriptors for the Glass catfish. 

The Glass catfish is a small freshwater fish found in native streams and river basins of Peninsular and Southeastern Thailand. They’re not known to breed in commercial facilities for the purpose of aquarium keeping, so most are wild-caught. This practice is understandably not sustainable, thereby explaining the Glass catfish’s relatively steep price tag. 

Throughout the years, this popular aquarium pet has undergone some confusion as to its exact species. It was originally thought to be Kryptopterus bicirrhis, a larger glass catfish that is not fully translucent. However, in 2013, the two species were finally differentiated from each other. K. bicirrhis was officially identified as the larger, aggressive ‘glass catfish’ that is only semi-translucent and rarely found in the fishkeeping hobby. 

Appearance

No doubt the most notable aspect of the Glass Cat is its uncommon appearance. The first thing you may assume is their size. Contrary to many peoples’ assumptions of the term catfish, these guys are quite small. They also have the barbels common among many catfish, but they don’t use them for rummaging in the substrate. Instead, these barbels are used in the detection of electromagnetic fields. 

Glass catfishes have the typical scaleless feature present in other catfishes; but unlike their relatives, the Glass catfish does not only lack scales, but pigment as well. In fact, this utter lack of pigment is what causes them to be as fully translucent as they are. Their translucence is so complete that all their organs and bones can be easily seen; a quality absent from other glass fish species. Sometimes, when the light is just right, you might even see the colors of the rainbow hitting the Glass catfish. This see-through feature is not merely for aesthetic purposes however. It’s actually a clever adaptation that helps this aquatic ghost avoid their natural predators and survive in the wild. 

Aside from their striking clarity, Phantom catfishes also lack a dorsal fin. They merely have a slight bump where the dorsal fin structure is supposed to go. As for their other fins, you probably can’t even find them at a glance. Their tail and ventral fins are so invisible, you’d think they weren’t even there. These fins are present however, and are responsible for helping the Phantom catfish make their way around the water. 

Average Size

Unlike many catfishes, the Glass Cat comes in a truly minuscule size. They have an average length range of only 2.1-2.6 inches. Naturally, they have the capacity to grow to their maximum lengths in their natural habitats in Southeast Asia. 

Lifespan

Rejoice! Though they are small, Glass catfishes have a life expectancy of around 7-8 years. Like all fishes, your aquatic friend can only reach a ripe old age with your proper care. Failing to provide your Phantom catfishes proper care will, of course, cause this lifespan to be cut short.

Glass Catfish Care Advice

In this comprehensive guide, we classified Ghost catfishes as moderately difficult to care for. This is primarily because of their electromagnetic sensitivity. Being sensitive to changes in their environments, Glass Cats are also sensitive to sub-optimal water conditions. The most minute mistakes can make them sick and lethargic, which can later on cost them their lives. 

But if you think you’ve got their water conditions handled, then you won’t have any other issues with the Glass catfish. Take a look at our care advice below for everything you need to know when keeping this see-through beauty. 

Tank Setup

Fortunately, these crystal-clear fishes have very minimal tank requirements. With only a bit of effort and thoughtfulness, you can give Glass Cats an enjoyable life in captivity indeed. Before you start off your aquascaping, it’s important to know the habits of your glass catfish. For example, they love hiding out, and very much prefer a dim tank. You can accommodate this by planting your tank with both tall and floating vegetation. Plants such as Broadleaves, Hornworts, Java moss and Java fern are good ideas; and Amazon Frogbits in particular will effectively shade your aquarium. Do not overfill the tank with too many plants though, these fishes love a bit of swimming space.

For additional hidey-holes, you can add rocks, logs, and cave-like structures to keep you Glass Cat happy. Set your tank up with a mild current as well, since these little beauties are no Olympic swimmers. The poor fellows will literally be carried away by a strong water current. 

Remember to be mindful of your structures and decorations, and make sure everything has a smooth surface. The tiniest sharp edges can cause injury to your fragile Glass catfish. This also applies to your choice of substrate. Harsh or coarse substrates will probably injure them, so stick to a soft sand substrate. 

Water Parameters

Probably the most essential part of caring for the Glass Cat is their water requirements. This aspect is what makes them best for seasoned or experienced hobbyists and not for beginners. As previously mentioned, these Ghost catfishes are very sensitive to changes in their environment; and because of their electromagnetic sensitivity, they also do not tolerate non-ideal water conditions in their tanks. So if you’re planning to get a Glass catfish, you must first and foremost be religious in their upkeep. Here are the strict water conditions for you to go by:

  • pH level: 6.5-7.0 (slightly acidic) 
  • Water hardness: around 8-10 dGH
  • Temperature: around 75°F-80°F or 24°C-27°C
  • Water flow: Mild to Moderate

Apart from keeping these parameters at their optimal state, it’s equally essential to perform water changes. Try to replace around 10% of the water weekly, and 20% monthly. Conduct cleanups, and make sure to place a good water filter in your tank.

Tip: While the above water conditions are the most important, make sure to also mind ammonia and nitrate levels in your Glass Cat tank. Keep ammonia levels at 0 every time, and the nitrates at less than 50 ppm.

Common Diseases

Much like their catfish relatives, the Ghost Cat is also susceptible to the diseases that befall the other members of its family. The scaleless trait of the Glass Cat adds to its vulnerability. First and foremost, the Phantom catfish have fragile skin and bones, and this makes them easy to wound. Mishandling or sharp ornaments can cause tears and injuries to this fish, so be gentle with them. As to the possible illnesses a Glass cat may get, there are no species-specific illnesses. You only need to watch out for the common freshwater aquarium diseases like: 

  • Ich- white spots on the fish body which may cause difficulty breathing for your fish.
  • Lice: Causes itching, and will urge your Glass cat to rub itself on ornaments to relieve themselves. This in turn, may cause bruising or wounds. 
  • Fin Rot- a bacterial infection that causes degradation of fish fins as if being eaten away.
  • Dropsy- Sometimes caused by bacteria, Dropsy is characterized by a bloated stomach in your fish, which causes them to be lethargic.
  • Fungal Infections- the scaleless nature of the Glass Cat can cause them to be vulnerable to a variety of fungal diseases. This manifests as white blotches on their bodies.

The silver lining in all of this is that you will quickly know if your Glass Cat is sick. Diseased Glass catfishes will lose their famed translucence and develop a milky, blurry color. This signifies that they are unwell and are battling some ailment. When this happens, immediately remove your sick fish and quarantine them for treatment. 

To lessen the chances of these fishes getting sick however, the most important thing is to watch their water parameters closely and make regular changes when needed. Clean their tanks frequently, including food debris on ornaments or stuck within the substrate.

Tank Size

Glass Cats are small fishes, however, they absolutely need to travel in schools. Naturally, since we want them happy, give them enough space for a school of at least 5 Glass Catfishes. Think of around 5 gallons per 1 glass catfish, with some space allowance; so a group of 5 would need a minimum of 20-30 gallons. 

Diet & Food

You’ll be amused to know that Ghost catfishes are actually picky eaters. While technically omnivorous, in reality they are selective and have their favorite meals.  In the wild, Glass Catfishes subsist on a diet of insects, worms, and smaller fish. Obviously, they prefer more meaty food than the convenient flakes. In fact, feeding them flakes and pellets feel very much like feeding petulant toddlers: It can be done, but it’s an uphill battle. 

Glass Cats are also reported to have fascinating feeding behavior, such as going up to the water surface when they know it’s time to eat. Choose slow-sinking food so you can be sure they catch their meals. Fussy Glass Cats don’t go after their food once it falls to the bottom, and instead stay on the mid-upper water regions. 

Glass Catfish Preferred food include:

  • Daphnia
  • Mosquito larvae
  • Bloodworms
  • Zooplankton
  • Brine shrimp
  • Grindal Worms
  • Bloodworms
  • Tubifex
Tip: Surprisingly, Glass catfishes have a tendency to be both underfed, and overfed by their owners. This can cause sickness, so stick to a feeding schedule of once or twice a day. Watch them eat as well, making sure other fishes don’t steal their meals.

Glass Catfish Breeding Behavior

Breeding Ghost catfishes have actually never been documented in an aquarium setting. As a matter of fact, those sold into the aquarium trade are usually caught directly from the wild. Admittedly, there are sustainability problems with this, because the Glass catfish is not known to breed in commercial facilities either. 

One of the difficulties in breeding these fishes is that Glass Ctas are not sexually dimorphic. This means that you absolutely cannot tell one sex from the other. They look completely the same. 

For those that are determined to spawn them regardless of the hurdles however, you can start by trying to imitate the conditions of their natural environment. 

There is some advice when it comes to their spawning, such as dropping the water temperature in your tank. Supposedly, the aim is to mimic the season Glass Cats usually spawn in. 

Another advice (though the effectiveness is questionable) is to replace their tank water with some natural freshwater. This is said to emulate the rainfall experienced by Glass Ctas in their native habitats. 

If the fishkeeping gods happen to smile upon your attempts, your breeding Glass catfishes will ‘kiss’ each other with their barbels. This indicates that they are in a breeding mood. If this mood pans out, Glass catfish eggs will be spread out on all your aquarium plants. These eggs then hatch in a few days. Feed your near-invisible fry some baby brine shrimp to start their tank life in the best way.

Glass Catfish Tank Mates

When it comes to making friends, there’s no better fish. They’re some of the most peaceful fishes you’ll come across, so choosing tank mates is an absolute breeze. Glass catfishes love swimming along with their own schools and keeping to themselves. Needless to say, this disposition makes them ideal for community aquariums.

Suitable Tank Mates for glass Catfish:

  • Other Glass catfish
  • Molly fish
  • Cory catfish
  • Swordtails
  • Calm tetras (Rummy Nose Tetra)
  • Harlequin rasbora
  • Celestial Pearl Danios
  • Peaceful Gouramis

As with most peaceful community fishes, you should avoid housing them with much larger or aggressive fishes. Examples of these fishes may be Cichlids, Tiger Barbs, and Arowanas. Instead, try to keep their community stress-free, and choose calm, similarly sized tank mates. 

Glass Catfish Temperament 

Glass catfishes might just be the complete opposite of aggressive. These fishes are the antonym of aggression. To put it simply, Glass Cats are calm, peace-loving fishes with an underlying timidity. This shyness usually presents itself when they are new to their surroundings. When shy or nervous, Glass catfishes will hide under rocks or inside caverns. Bright lighting can also urge them to hide. 

They’re not shy forever though. Once these translucent little guys become comfortable, they can be very social. In fact, they are very energetic swimmers, especially when you keep them with their shoal. They much prefer being with each others’ company than without, as this gives them all comfort. When it comes to other fish species, Glass Cats are even-tempered and don’t do their tank mates any harm (awww). Even if you’ve accidentally placed aggressive fish with them, Glass catfishes usually choose to scurry away and hide. Better to flee and live another day, I always say. 

Conclusion

Now that you know all about the Glass catfish, you’re most likely itching to go and get one. Understandable, since they are peace-loving, perfect for community tanks, and magnificently translucent!  

Before you run down to the store however, take time to think about the amount of care these fish need. Glass catfishes are not beginner fish. They are best introduced to already cycled and established freshwater aquariums, and they have strict water requirements. They can also be picky eaters. 

However, if you’re no newbie and are more than up for the challenge, by all means get these Ghost catfishes! No other species can give quite the ethereal skeleton look they can, lending your tank some much needed novelty.

Note: Please consider the environment before printing this Glass Catfish care sheet.

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