Glowlight Tetra
Fish
Beastly Facts · Updated
The easygoing schooler with a stripe that glows like a lit fuse!
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Did you know? The glowlight's stripe is a band where the dark pigment cells are missing: the species name, erythrozonus, means red-banded, and a 1917 scientific description called the stripe cherry-red in life.
The first week
The numbers a new owner needs in the first week, each from the article it links to. Rows with no link come from the encyclopedia.
- How many
- Ten or more, with six the least that counts as a school.Handling guide →
- Tank size
- A base of at least 24 x 15 inches (60 x 38 cm), roughly 18 to 20 gallons, for a school of 10. A 10-gallon falls short of that base.Setup guide →
- Temperature
- 75 to 82°F (24 to 28°C), held steady with a heater set inside the range. 82°F is the top.Setup guide →
- Water chemistry
- pH 5.5 to 7.5 and 2 to 15 dGH. Fish kept on the acidic side of that pH range show more color.Setup guide →
- Cycle first
- Cycle the tank fully before the school goes in.Setup guide →
- Plants
- A good spread of fine-leaved plants at several heights, with a clear stretch of open water in the middle for the school.Setup guide →
- Diet
- Micropellets or small flakes day to day, with bloodworm, daphnia and brine shrimp as live or frozen extras. They take almost anything offered.Feeding guide →
- Feeding schedule
- Once or twice a day, each feeding light: only what the school finishes.Feeding guide →
- Acclimation
- Dim the room, then add a little tank water to the bag every few minutes for 30 to 60 minutes. Net the fish across and leave the bag water behind.Handling guide →
- Tankmates
- Lively and peaceful, at home with other small, calm fish. Not with angelfish: a full-grown angelfish treats a 1.6-inch tetra as food.Handling guide →
- Quarantine
- At least 30 days in a separate tank before new fish meet the school.Health guide →
- Ich
- No heat cure: most strains die above 86°F and the glowlight's range stops at 82°F. Warm slowly to 82°F with an air stone and treat with an ich medication, in soft water one without copper. Salt is unproven for this species at the 4 to 5 grams per liter that kills ich.Health guide →
- Water changes
- 25 to 30% weekly from the substrate, with conditioned water at tank temperature. Test nitrate first: under 20 ppm the routine is right, past 40 ppm the next change is 50%.Aquarium Water Changes →
- Budget
- About $3 to $5 a fish; ten come to $30 to $50. Setup roughly $165 to $380.Cost guide →
- Lifespan
- About 2 to 4 years.Cost guide →
- Adult size
- About 1.6 inches (4 cm).
- Power outage
- Oxygen is the threat, not darkness. Unplug the filter rather than letting it sit dead in the water, and keep the surface moving.Power outage guide →
Emergency card
Test ammonia and nitrite first, then act on these today.
- Fish gasping at the surface or breathing fast
- Two or more fish showing the same sign at once
- A fish found dead: take the body out of the tank before anything else
- White spots like grains of salt on the body or fins: start treatment today
- Fins that look shortened, ragged or reddened along the edges, worse than the day before
- Fast breathing that continues once the water tests clean, since ich can infect the gills
Watch closely and check again tomorrow.
- Flashing: rubbing against plants, glass or substrate
- A fish off its food or hanging listless
- Fins held clamped against the body
- Color fading to dull
Most of what goes wrong starts in the water or arrives with a new fish, so test first and quarantine every newcomer.
Where to go next
How Much Does Glowlight Tetra Ownership Cost?
$3 to $5 a fish, the school of ten to price, and the $165 to $380 for the tank around them.
Glowlight Tetra Tank Setup: A 24 x 15 Inch Base, Acidic Water, and Planted Cover
A 24 x 15 inch base for ten, 75 to 82°F, acidic water for color, and planted cover around open water.
Glowlight Tetra Feeding: Diet, Live Foods, and How Often to Feed
Once or twice a day, kept light, an easy eater, and food for fry.
Glowlight Tetras Are Never Handled, So the Trip Home and the Tankmates Matter
Acclimation over 30 to 60 minutes, the school of ten, and why angelfish are off the list.
Common Glowlight Tetra Health Issues (and Why the Ich Heat Cure Stops at 82°F)
Why the ich heat cure stops at 82°F, the 30-day quarantine, and the signs that need action today.
Glowlight Tetra Enrichment: A School, Open Water and Stained-Stream Cover
Tannins, leaf litter and planting that bring out the stripe and settle the school.
What to buy
As an Amazon Associate I earn from qualifying purchases. Underlined items are paid Amazon links, at no extra cost to you.
Prices and the reasoning behind each item are in How Much Does Glowlight Tetra Ownership Cost?.
Full Glowlight Tetra gear listFrequently Asked Questions
What size tank do glowlight tetras need?
A tank with a base of at least 24 x 15 inches (60 x 38 cm), roughly 18 to 20 gallons, for a school of 10. A 20-gallon long has the same floor area.
How often should glowlight tetras be fed?
Once or twice a day, keeping each feeding light. Give only what the school finishes, since uneaten food fouls the water.
Can you cure ich in glowlight tetras with heat?
Heat alone will not do it. The temperature that kills most ich strains is 86°F, and a glowlight's range stops at 82°F. Warm the tank slowly up to 82°F with an air stone running to speed the parasite's cycle, and treat with an ich medication. Salt is unproven for this species at the 4 to 5 grams per liter that kills ich.
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