It’s easy to see why these fish are so popular in aquariums. Their transparent bodies immediately catch the eye, which is why they’re called glass catfish.
They’re also known by a few other names – ghost fish, glass cat and phantom catfish.
This guide will help you learn how to care for glass catfish. You’ll find that it’s simpler than you might expect.
| Common name(s) | Phantom catfish, Glass catfish, Glass cat, |
| Binomial name | Kryptopterus vitreolus |
| Care Level | Moderate |
| Temperament | Peaceful |
| Size range – lenght | 3-4 inches |
| Water parameters | Temp 75-80°F (24–27°C) pH 5.5–6.5 Hardness 5-12 dGH |
| Tank level | In the middle |
| Diet | Omnivore |
| Lifespan | 7-8 years |
| Breeding | Egg-layers |
| Tank mates | Swordtails, Mollies, Celestial Pearl Danios, Peaceful tetras, Guppies, Danios, Corydoras, Small Plecos, Gouramis, |
Origin
Glass catfish come from Southeast Asia and live in overgrown reservoirs alongside other peaceful fish like tetras. They inhabit the fast-flowing rivers and streams of Thailand and Malaysia.
The species name “vitreolus” comes from the Latin word “vitreus,” meaning glass.
The glass catfish was once thought to be Kryptopterus bicirrhis. However, this name is actually for a larger and more aggressive type of glass catfish that is rarely found in the aquarium trade.
In this guide, we focus only on the species commonly kept in aquariums, Kryptopterus vitreolus.
In the aquarium trade, there are several similar species of Kryptopterus, which can be hard to tell apart. T
wo other species, K. minor and K. piperatus, also have clear bodies, but they are not typically found in the aquarium trade.
Size
Glass catfish typically grow to about three and a half inches long, but their size can vary by species. For instance, the Cryptocorus minor species is smaller.
Availability
Glass catfish are easy to find in aquarium stores and usually cost around five dollars for the smaller ones.
However, it’s important to note that they should be kept in groups, not alone.
Appearance and Sex Differences
The most noticeable feature of this fish is its unique appearance. It has a long, flattened body with no extra fins like the adipose and ventral dorsal fins.
Its tail fin points downward, and it moves using a wide anal fin that runs along almost the entire underside of its body. The fish steers with its large pectoral fins.
A key feature of the ghost catfish is its very long whiskers, which stick out straight and act as sensors.
These whiskers are highly sensitive to changes in their surroundings and can even detect electromagnetic waves.
Scientists are studying these whiskers to see if they could help with medical conditions like epilepsy or Parkinson’s disease in the future.
What’s most remarkable is the fish’s almost transparent body. You can see through its skin to its skeleton and internal organs, though the head is slightly darker with black spots.
This transparency helps the fish blend in and avoid predators, making it harder for them to be seen and eaten.
Sexual dimorphism does not occur in these fish.
Behavior
The fish is friendly and social. They should be kept in groups of at least 10 individuals.
You can also keep other small Asian fish with them, like Danios and Rasboras.
They look very impressive in a school. Viewing a group of 10 or more swimming together in the aquarium is striking.
Despite being catfish, they prefer to stay in the middle of the tank and swim in the water column. When undisturbed, they may hide within the tank.
One interesting thing about them is that they often stay in one spot at a certain level in the tank, almost as if they are frozen in place.
Care
Taking care of these fish is easy as long as you mimic their natural habitat.
In the wild, glass catfish blend in because the water is usually murky and their transparent bodies help them hide from predators.
They might be shy and hide during the day but are more active in the evening or in low light. To make them feel safe in your aquarium, provide hiding spots.
They eat all kinds of fish food available in stores, and it’s best to keep them in groups of at least 10.
Tank Requirements
The tank for glass catfish should have low light and a gentle filter to keep the water clear without strong currents.
It is worth installing an efficient air pump in the tank.
At the bottom, use a layer of coarse sand. Add decorations like pieces of wood, roots, coconut shells, and dry leaves.
You can also cover part of the sand with dry leaves. Avoid sharp or rough substrates as they can hurt the fish’s whiskers.
The aquarium should be well-plante but having too many plants in the tank can limit their swimming space.
Adding a small amount of tannins, which you can get by filtering water through peat or using special products, is good for the fish.
Glass catfish are sensitive to waste buildup in the tank, so do regular water changes of up to 15% of the tank’s volume each week.
Keeping glass catfish is not very difficult if you maintain the right water conditions. They are sensitive to changes in temperature, pH, and other water chemistry factors.
Aim for a water temperature of 75-80°F, a hardness level of 5 to 12, and a pH between 5.5 and 6.5.
They are not ideal for beginners, but with some experience, you should be able to care for them without issues.
The best tank size for glass catfish is at least 30 gallons, with more space being better.
For a 30-gallon tank, you should plan for about 5 gallons per fish. A group of 6 is the maximum recommended, but it’s best to keep them in groups of 10 or more but in bigger tank.
Diseases
Ich (Ichthyophthirius multifiliis)
Often referred to as “white spot disease,” ich is caused by a protozoan parasite that attacks the skin, gills, and fins of fish.
Symptoms include white cysts on the skin, rapid gill movement, and increased scratching against objects.
Treatment typically involves raising the water temperature and using an anti-ich medication.
Velvet Disease
Velvet disease is caused by a protozoan parasite that leads to a dusty or velvety appearance on the skin.
Affected fish may rub against objects and exhibit respiratory distress. Treatment includes raising the temperature and using copper-based medications.
Columnaris
This bacterial infection can cause white or grayish patches on the skin and gills, as well as rapid gill movement and loss of appetite.
Improving water quality and using antibiotics can help manage the disease.
Parasites
Glass catfish can be affected by various external parasites, such as skin flukes or gill flukes.
Symptoms may include abnormal behavior, scratching, or visible parasites on the skin or gills.
Treatment generally involves anti-parasitic medications.
Fungal Infections
Fungal infections can appear as cotton-like growths on the skin or fins. These infections often follow injuries or poor water conditions.
Treatment involves improving water quality and using antifungal medications.
Tank Mates
Glass catfish do very well in community tanks. Community tanks are those that consist of several species of peaceful fish that do not attack each other.
All livebearers such as swordtails, molly or guppies will do well. They can be kept with peaceful tetras and various species of danios.
Corydoras and small plecos will also be suitable.
Ensure that the tank mates have similar water parameters. Glass catfish thrive in slightly acidic to neutral water with moderate hardness and temperature.
Fish that are known for aggressive or territorial behavior, such as some cichlids or large barbs, can stress out glass catfish and potentially harm them.
Tiger barbs, oscars, red tail sharks are not suitable for this aquarium because they can be too aggressive.
Very active and fast-moving fish, like some types of danios or certain species of tetras, might be too boisterous for the more delicate glass catfish.
While not aggressive, their high activity levels might stress the glass catfish.
Diet
In their natural environment, they mainly eat small, rounded worms or other small invertebrates. They can also eat tiny fish and mosquito larvae.
It’s best to feed them frozen food, such as worms, Grindal worms, daphnia, brine shrimp, and moina.
They will also eat granules or flakes, but those that fall into the water column are not eaten as eagerly by the fish.
Feed them about twice a day and avoid overfeeding. Since they are shy by nature, you need to ensure that they actually eat the food.
Other species of fish, even if they are peaceful, may be more aggressive in going after food, which can intimidate your Glass Catfish.
Breeding
No one has yet observed how these fish spawn, but it’s interesting that they can breed in aquariums.
Many fishkeepers have noticed more glass catfish in their densely planted tanks than they originally placed there.
It’s likely just a matter of time before we discover the secret to their spawning, especially since these fish are regularly bred on Asian ornamental fish farms in ponds.
In the wild, these fish breed during the rainy season, which brings heavy rainfall.
In fish tank, this can be mimicked by lowering the water temperature to around 73°F and adding small amounts of fresh water daily.
This change in temperature and water simulates the rainy season, encouraging the fish to breed.
During this period, it’s also important to feed them plenty of live food, as in the wild, they would have access to an abundance of food needed for reproduction.
If you succeed in breeding these fish, the female will lay eggs on the plants in the aquarium.
The eggs will hatch after 3-4 days. The tiny fry will be small, but big enough to eat young Artemia larvae.
In conclusion
This fish may seem difficult to care for, but with a bit of patience, anyone can manage it.
However, I wouldn’t suggest it for beginners in fishkeeping. The aquarium conditions need to be just right.
Otherwise, the fish can become stressed and ill. This can be particularly challenging for those new to the hobby.
But if you’ve already learned from the common beginner mistakes I’ve mentioned in other articles, you can certainly consider getting this fish.
It will enhance the beauty of your aquarium and impress anyone who sees it.
