Best Tank Mates for Glass Catfish: Compatible Fish and Species to Avoid

The best tank mates for glass catfish are small, peaceful fish under about 3–4 inches (7.5–10 cm) that like soft, warm tropical water: ember, neon and cardinal tetras, harlequin rasboras, Corydoras, kuhli loaches, honey gouramis, amano shrimp and nerite snails. Skip cichlids, fin-nippers like tiger barbs, red-tail and rainbow sharks, large catfish, predators and goldfish. Before any of that, though, remember that the most important tank mate for a glass catfish is a group of other glass catfish.

Know Your Fish First

Which "glass catfish" are you buying?

The see-through catfish in stores today is almost always Kryptopterus vitreolus, which reaches roughly 2–3 inches (5–7.5 cm). Many labels still read K. bicirrhis, an older name that properly belongs to a larger species that is rarely imported. The practical takeaway: plan for a small, delicate fish, not a big one.

How they behave, and why it shapes every choice

Glass catfish are timid, shoaling midwater hoverers. A healthy group hangs together in open water, facing into a gentle current like a row of tiny kites. That behavior drives tank-mate selection in three ways:

• They occupy the middle of the tank. Pair them with top and bottom dwellers so the midwater zone doesn't get crowded.
• They need steady, moderate flow. Mates that demand dead-still water are a poor fit.
• They are easily stressed. Anything that chases, nips or grabs food aggressively will push them into hiding.

Kept alone or in pairs, glass catfish hide, stop eating and often die. Buy at least 6; 8 or more is better and noticeably bolder. Sources split between 5 and 6 as the minimum, so err on the larger side.

Tank and Water Requirements

Size the tank for the catfish, not for the smallest companion. Some compatibility lists mark a tetra as fine in 10 gallons, but a glass catfish school still needs far more room.

• Tank size: 30 gallons (114 L) is the common minimum for a school plus companions. A 20-gallon long (76 L) is a floor only for a small group with very few other fish.
• Temperature: 75–80°F (24–27°C)
• pH: about 6.5–7.0
• Hardness: soft to moderately hard, roughly 5–12 dGH. Published KH figures vary widely; stability matters more than hitting an exact number.
• Water quality: zero ammonia and nitrite. These fish are sensitive to swings, so add them only to a fully cycled, mature tank.
• Décor: dense stem plants, floaters and moss, subdued lighting, a clear midwater swimming lane, and smooth sand or fine gravel.

With good care, glass catfish commonly live around 7–8 years, so choose companions you'll be happy with long term.

The Three-Filter Test for Any Tank Mate

Run every candidate through these checks:

1. Size: Adults should stay under about 3–4 inches (7.5–10 cm). If a fish's mouth can fit around a glass catfish, it's out.
2. Temperament: Peaceful only. No fin-nippers, no territorial bullies, and no "semi-aggressive community" fish sold as compatible.
3. Water and feeding match: Similar soft-ish tropical water, and not a glutton that clears the food before the catfish get any.

Best Tank Mates for Glass Catfish

Midwater and upper-level schoolers

• Tetras: ember, neon, cardinal, black neon, glowlight, lemon and rummy-nose tetras. Small, peaceful and happy in the same water. Browse tetras on FishyHub when you're ready to stock.
• Harlequin rasbora: calm, colorful and a good match for planted, dim tanks.
• Celestial pearl danio: tiny and shy; best in a heavily planted setup.
• Cherry barb: calmer than most barbs and a safe exception to the "no barbs" rule.
• Hatchetfish: they cruise the surface, leaving midwater free. They jump, so a tight lid is required.
• Dwarf neon rainbowfish: active, so reserve them for larger tanks.

Bottom dwellers

• Corydoras: keep groups of 6 or more over sand. Pygmy and panda cories suit smaller setups. See the Corydoras selection.
• Kuhli loaches: secretive, peaceful and good at cleaning up leftovers.
• Otocinclus: only in a mature tank with plenty of biofilm to graze.
• Bristlenose pleco: a practical algae eater for tanks of 30 gallons or more.

Centerpiece fish

• Honey gourami or sparkling gourami: gentle, and they use the upper water column.
• Dwarf gourami: one only, and watch for territorial behavior.
• Peaceful livebearers: platies, Endlers, mollies and swordtails can work if your water isn't too soft (see the hardness table below).

Invertebrates

• Amano shrimp and adult neocaridina shrimp are safe.
• Nerite snails are fine and help with algae.
• Tiny shrimplets may be eaten, so don't count on a shrimp colony growing in the same tank.

Compatibility at a glance

Species	Zone	Adult size	Rating	Notes
Ember / neon / cardinal tetra	Mid	~1–1.5 in (2.5–4 cm)	Excellent	Same soft, warm water
Rummy-nose / lemon / glowlight tetra	Mid	~1.5–2 in (4–5 cm)	Excellent	Keep in groups
Harlequin rasbora	Mid	~2 in (5 cm)	Excellent	Likes plants and dim light
Cherry barb	Mid	~2 in (5 cm)	Good	Calmer than other barbs
Hatchetfish	Top	~1.5–2.5 in (4–6 cm)	Good	Needs a tight lid
Corydoras	Bottom	~1–2.5 in (2.5–6 cm)	Excellent	Groups of 6+ on sand
Kuhli loach	Bottom	~3–4 in (7.5–10 cm)	Excellent	Needs hiding spots
Honey / sparkling gourami	Top	~1.5–2 in (4–5 cm)	Excellent	Gentle centerpiece
Platy / Endler	Mid–top	~1–2.5 in (2.5–6 cm)	Good	Moderate hardness
Zebra danio	Top–mid	~2 in (5 cm)	Caution	Big group, big tank only
Mollies / large swordtails	Mid	~3–4+ in (7.5–10+ cm)	Caution	Harder water, can be pushy
Amano shrimp / nerite snail	Bottom	~1–2 in (2.5–5 cm)	Excellent	Shrimplets at risk

Species to Avoid

• Cichlids: oscars, jack Dempseys, convicts and even many mid-size South American cichlids are too large or too aggressive.
• Tiger barbs and other fin-nippers: constant harassment keeps glass catfish hiding.
• Red-tail and rainbow sharks: territorial and pushy.
• Large catfish, arowanas and other predators: a glass catfish is simply a meal.
• Angelfish and adult discus: this one is debated. Adult angels can eat small catfish, and both outcompete them at feeding time. Treat it as risky.
• Bettas in small tanks: an aggressive male in cramped quarters is a bad combination (see the FAQ).
• Goldfish: they want cooler water and produce heavy waste.

The gray areas: livebearers and zebra danios

Some keepers rate guppies, swordtails and mollies highly; others note that bigger swordtails can be pushy and that mollies prefer harder water. They're acceptable in larger tanks with matching hardness, but skip them in soft, tight setups. Zebra danios also get mixed reviews. They're hyperactive and can nip, so keep them only in big groups in a roomy tank.

Hardness matching: soft-water fish vs livebearers

Group	Preferred hardness	Fit with glass catfish (~5–12 dGH, pH 6.5–7.0)
Tetras, rasboras, cories, kuhlis	Soft to moderate	Natural match
Honey / sparkling gourami	Soft to moderate	Natural match
Platies, Endlers	Moderate to harder	Works near the upper end of the range
Swordtails, mollies	Harder, often higher pH	Only if you run moderately hard water in a large tank

Sample Stocking Plan: 30 Gallons (114 L)

• 8 glass catfish (midwater)
• 10 ember or cardinal tetras (midwater, lower density)
• 6 pygmy or panda Corydoras (bottom)
• 1 honey gourami (upper level)
• A few nerite snails and amano shrimp (cleanup)

Every zone gets used without crowding the catfish's midwater lane, and every species shares the same water.

Feeding With Faster Competitors

Glass catfish eat from the midwater and aren't fast. Offer micro-pellets or flakes plus frozen or live daphnia, brine shrimp, bloodworms and grindal worms, in 1–2 small feedings a day.

• Feed into the current where the catfish hover so food drifts past them.
• Use slow-sinking foods rather than only floating flakes that surface feeders grab.
• Watch each feeding. If danios or large livebearers are taking everything, target-feed or rethink the stocking.

Introducing, Quarantining and Acclimating

• Quarantine every new fish for 2–4 weeks in a separate tank before adding it.
• Add glass catfish first or into a calm tank, and bring in boisterous species last.
• Acclimate slowly. Because these fish are sensitive to swings, match temperature and chemistry gradually rather than dumping them in.
• Keep lights low for the first few days after introduction.

Indian Glassfish Tank Mates (Don't Confuse the Two)

The Indian glassfish (Parambassis ranga) is also transparent, but it's a perchlet, not a catfish, and its care is different. It prefers slightly harder, neutral-to-alkaline water (pH ~7–8) and tolerates low salt. Suitable peaceful mates include white cloud minnows, rosy tetras, danios, cherry barbs, honey gouramis, platies and bristlenose plecos.

Avoid dye-injected "painted" glassfish. The bright colors come from artificial dye, a practice that harms the fish; choose naturally clear specimens.

Common Mistakes and Troubleshooting

• Buying only 1–3 catfish: they hide and waste away. Grow the school to 6–8+.
• Stocking a new, uncycled tank: leads to sudden losses. Wait until the tank is mature.
• Flow that's too strong or absent: aim for gentle, steady current.
• A bright, bare tank: causes skittishness. Add floating plants and cover.
• Being outeaten by fast fish: target-feed with slow-dropping foods.
• A cloudy or white body: a healthy glass catfish is clear. Cloudiness signals stress or disease, so test the water immediately.
• Trusting "semi-aggressive community" labels: these fish often turn out to be nippers.

Frequently Asked Questions

Can glass catfish live with bettas?

It's possible in a 20–30 gallon (76–114 L) tank with a calm male and dense plants, but it isn't ideal. Bettas prefer still water, while glass catfish like gentle flow. An aggressive betta in a small tank should be avoided.

Will glass catfish eat shrimp or fry?

Adult shrimp are safe. Baby shrimp and small fry may be eaten, and those are the only fish they'll prey on. Otherwise glass catfish are harmless to other fish.

Can glass catfish go with angelfish?

It's risky. Adult angelfish can eat small glass catfish and will outcompete them at feeding time. Choose smaller centerpieces like honey or sparkling gouramis instead.

Are glass catfish good for a 10- or 20-gallon tank?

A 10-gallon (38 L) tank is too small. A 20-gallon long works only for a small school with few tank mates. For a proper school plus companions, plan on 30 gallons (114 L).

Why do my glass catfish hide all the time?

The usual causes are too few in the group, bright lighting, aggressive tank mates or poor water quality. Test the water, add floating plants and enlarge the school.

Do glass catfish and Indian glassfish need the same care?

No. They belong to different families, and the Indian glassfish prefers harder, neutral-to-alkaline water with tolerance for a little salt. Glass catfish do best in softer water around pH 6.5–7.0.

Build a Calm Community

Get the school size and water right, then add small, peaceful fish that use the top and bottom of the tank, and glass catfish will spend their time out in the open. You can browse suitable tetras, rasboras and other peaceful companions in FishyHub's Small Community Fishes category.