Glass catfish are transparent aquarium fish whose bodies add an interesting aesthetic to the freshwater aquarium.
Unlike other species, the peaceful glass catfish swims in the center of the aquarium. They are active and often dart back and forth across the tank.
They are one of the more difficult catfish species to care for. Still, many fish keepers find caring for them to be rewarding.
What Is The Glass Catfish?
There are several types of glass catfish, all of which are a type of transparent fish species. The most common glass catfish in the aquarium trade is the Kryptopterus vitreolus.
Misidentified For 80 Years
For about 80 years, this species was misidentified as the Kryptopterus bicirrhis. K. bicirrhis is a type of glass catfish, but they are far more aggressive than K. vitreolus. They are also rare in the aquarium trade.
Researchers Heok Hee Ng and Maurice Kottelat distinguish K. vitreolus from K. bichirrhis by its physical characteristics.
They say that K. vitreolus has a combination of, a “transparent body in life, maxillary barbels reaching beyond the base of the first anal-fin, dorsal profile with a pronounced nuchal concavity, snout length 29–35% head length (HL), eye diameter 28–34% HL, slender body (depth at anus 16–20% standard length (SL)) and caudal peduncle (depth 4–7% SL), 14–18 rakers on the first gill arch, and 48–55 anal-fin rays.”
What Do Glass Catfish Look Like?
Their bodies are long and slim with transparent skin that allows you to see the bones and organs. Their scientific name translates to “hidden fin”. Their tail fin is so transparent that it’s almost impossible to see.
Down the center of the body is the central spinal column. All along the spinal column are vertical ribs. At the end of the body is their small, near-invisible tail. The upper part of their back is slightly raised to accommodate their dorsal fin. Their ventral fin sits on the underside of their body. Both of these fins are also transparent.
Their head and upper body are their most striking features. Just behind the head is where you’ll see the dark organs within their clear body.
Their Bodies Offer Protection
Two barbels protrude from the front of their face — typical for the catfish species. Barbels are sensory organs that allow the catfish to sense what is around them. They are native to rivers and streams where the visibility is low. Glass catfish aren’t as adept at navigating murky waters as other catfish species. So, barbels are essential to their survival.
Their invisible body acts as protection against predators — they can’t eat what they can’t see. A transparent body allows glass catfish to blend in with nearly any background. Still, they prefer to hide among plants.
If they receive proper care, glass catfish will live for about 8 years or more.
- Common Names: Glass catfish, ghost catfish, phantom catfish
- Scientific Name: Kryptopterus vitreolus
- Origin: Southeast Asia — Thailand
- Glass Catfish Size (Length): 4-6 in (10.2-15.2 cm)
- Aquarium Size: 30+ gallons
- Temperament: Peaceful
- Ease of Care: Moderate
Habitat
Glass catfish are native to the flowing rivers and streams of Thailand. According to Fishbase, they live in “Peninsular and southeastern Thailand; absent in central Thailand”.
They are most often found in the rivers that connect to the Gulf of Thailand. There are some populations that live in the river basins of the Cardamom Mountains.
These catfish are unique in that they prefer to swim about the middle of the water column. Most species of catfish are bottom feeders and sift amongst rocks. Still, glass catfish will use the rocks and nearby vegetation for protection.
How Big Do Glass Catfish Get?
Glass catfish are medium-sized fish that will grow to a length of about 4-6 in (10.2-15.2 cm).
Behavior & Temperament
Glass catfish are free-swimming fish who travel in schools. Shy and fearful, glass catfish feel safer in numbers. They are peaceful and will stick together, rarely bothering any other fish in the tank.
When you first introduce them to your tank, they may not move around very much out of nervousness. After a few days or weeks, you will notice them become more active.
Glass Catfish Care
Generally, glass catfish are a good option for beginners. They are not difficult to take care of but are sensitive to fluctuations in water quality.
Glass catfish are tropical fish who do best in water temperatures between 75-80°F (23.9-26.7°C). The water hardness should be between 8-12 KH and 8-10 dGH, and the pH should be between 6.5-7.0.
The good news is they are not prone to any particular diseases. But, their sensitivities to water quality can leave them more susceptible to illness. Be careful to maintain consistently healthy water conditions. Otherwise, they will develop illnesses like bacterial and fungal infections.
Glass Catfish Tank Size & Decorations
A full-grown glass catfish will reach a length of about 5 in (12.7 cm). Their larger size means that they need a bigger tank — at least 30 gallons.
They are schooling fish, meaning that you should have at least six glass catfish in your tank. So, they’ll need plenty of space to swim around.
If you want more than six glass catfish, plan on adding an extra five gallons for each extra catfish.
If you are planning to put together a community tank, you should plan on investing in a tank that is at least 50 gallons.
A larger tank also helps these catfish feel more secure. They are a fearful species, so a large tank gives them more space to swim and hide away from their tank mates.
You should mimic their natural habitat by providing plenty of aquatic vegetation. Live plants give the fish cover to hide in and feel secure. Plants also help to block out light which can be stressful for them. They prefer lower levels of light where their bodies can better blend in. For their comfort, avoid lights that are too bright, instead opting for a softer glow.
You’ll also want to take care with the substrate you choose. A glass catfish’s body is more fragile than that of other catfish species. So, they can damage themselves on sharp rocks and gravel. Instead, choose a soft substrate like sand. If you have other catfish species in the tank, you can supplement the substrate with rocks.
Water Flow
Native to rivers and streams, glass catfish like a moderate amount of flow. The right amount of flow will keep them active and will provide them with the right amount of oxygen.
For this species, a filter usually isn’t enough. Instead, provide them with a powerhead that has an adjustable flow rate. Aim the powerhead around the middle of the tank where the fish are most active. Make sure to leave an area of the tank outside of the flow so they have a place to rest.
What Do Glass Catfish Eat?
Glass catfish are omnivores. They like to eat zooplankton, small worms, and small invertebrates in the wild. Although it doesn’t happen often, they will sometimes eat small fish as well.
In captivity, you’ll want to mimic this high-protein diet. Tropical flakes and pellets should make up their staple diet. Supplement them a few times a week with meaty snacks. You can choose things like frozen or live daphnia, brine shrimp, or blood worms.
Remember that glass catfish are shy and timid, so certain tank mates may bully them away from the food. Watch them during feeding to make sure they are getting enough food.
Glass Catfish Tank Mates
Glass catfish make good additions to peaceful freshwater community tanks. They are peaceful fish who do not bother other animals in the tank. Instead, you’ll need to worry about other fish species bullying your catfish.
Be careful to only choose species that are also peaceful and calm. Species that are peaceful, but too active, may stress out your glass catfish.
Some good tankmates for your glass catfish include:
- Other peaceful catfish like bumblebees, cory catfish, and upside-down catfish
- Swordtails
- Kuhli Loaches
- Mollies
- Danios
- Larger tetras
Avoid large and/or aggressive species including:
It is also essential that you keep glass catfish in schools of at least five to six individuals. Don’t try to keep a single glass catfish as it will stress them out and likely lead to death. They find safety in numbers, and it’s rare to see a glass catfish go anywhere alone.
Can You Keep A Glass Catfish With Betta Fish?
Whether you can keep glass catfish with a betta fish depends on the temperament of the betta. Some people will try to tell you that you shouldn’t keep bettas with any other fish, but this isn’t true. Many bettas can live in peaceful community tanks.
Most often, bettas are only a threat to other fish that look like them. For example, you shouldn’t place them in tanks with fish like guppies or swordtails. Their bright colors and long, flowy fins are seen as a threat.
Fish with short fins and subdued colors are rarely in danger from bettas. So, a betta is likely to do well in a tank full of glass catfish.
Just use caution as each betta has its own personality and some are more aggressive than others.
How Does the Bumblebee Catfish Compare To Other Catfish?
Are you not sure if a bumblebee catfish is right for your aquarium? See how they compare to other common freshwater species.
Conclusion
These see-through catfish are more sensitive to water quality. But, with gentle care, they make a good addition to freshwater community tanks. Their transparent bodies offer a unique look to the tank. Plus, unlike most catfish, they actively swim throughout the water column.
FAQs
Glass catfish are omnivores. But, they tend to prefer meatier foods like daphnia and bloodworms. They will not actively eat algae or plant matter, so you should not rely on them to keep your tank free of algae.
Fish are not a part of a glass catfish’s typical diet. They tend to prefer zooplankton, small worms, and small invertebrates. Still, they may eat small fish if they have the chance. So, be cautious when choosing tank mates for your glass catfish.
Glass catfish are a shy and fearful species. They will not bother other fish and are non-aggressive, so they will not nip at other’s fins.
Glass catfish are not nocturnal, but they don’t like bright lights. They prefer subdued lighting. So, they are likely to be more active at night when the lights are off or dimmed.
Researchers do not yet fully understand how fish can have transparent bodies. Still, they have a few theories.
They theorize that glass catfish have slender bodies with less potential for scattering light. It’s also likely that small molecules within the fish’s body are packed in a specific order that further reduces scattering. Lastly, it’s likely that subcellular components like the mitochondria are tiny and well dispersed to produce transparent tissues.
