Glowlight rasbora

1) Where they come from

Glowlight rasboras (Trigonostigma hengeli) come from blackwater streams and swampy forest areas in Southeast Asia (think Malaysia/Sumatra region). The water there is often tea-stained from leaf litter, with soft bottoms and lots of roots and plants. That vibe explains pretty much everything they like in an aquarium.

2) Setting up their tank

These are small, easy fish, but they look and act way better when you lean into a calm, planted tank. You don’t need anything fancy—just a stable, cycled aquarium and a layout that makes them feel covered.

• Tank size: 10 gallons can work for a small group, 15–20 gallons feels noticeably nicer (more swimming room, steadier water).
• Group size: get 8–12 if you can. They’re a different fish in a real shoal—more confident, more visible, better color.
• Filtration: gentle flow. A sponge filter or a baffled HOB works great.
• Plants: yes please—Crypts, Java fern, Anubias, stem plants, floating plants. They love broken-up sightlines.
• Substrate: darker looks best and makes them less skittish, but anything is fine.
• Lighting: moderate. If it’s bright, add floaters to soften it.

For parameters, aim for typical community-tank ranges: mid-70s to low-80s °F (24–28°C) and clean, low-nitrate water. They don’t like a tank that swings around a lot, so keep up with small weekly water changes rather than big random ones.

3) What to feed them

They’re not picky, but their mouths are small. Most “they won’t eat” stories are really “the food is too big” stories.

• Staples: crushed flakes, micro pellets, nano granules.
• Frozen: baby brine shrimp, daphnia, cyclops (great for color and condition).
• Live (if you do it): baby brine shrimp is basically a cheat code for getting them looking their best.

4) Behavior and tankmates

Glowlight rasboras are peaceful, slightly shy at first, and they do that classic rasbora shoaling thing—tighten up when startled, then relax and cruise around once they feel safe. In a planted tank they’ll spend more time out in the open.

• Great tankmates: other small calm fish (chili rasboras, harlequin rasboras, small tetras), Corydoras, Otocinclus, kuhli loaches.
• Inverts: usually fine with shrimp, though tiny baby shrimp may get picked off like with most small fish.
• Avoid: nippy fish (some barbs), bigger boisterous fish, or anything that treats them like a snack.

5) Breeding tips (if you feel like trying)

They’re egg scatterers, and they’ll absolutely eat their own eggs if they find them. Breeding isn’t hard, but it’s one of those setups where the details matter more than the fish.

• Use a small breeding tank (5–10 gallons) with a sponge filter and very gentle flow.
• Add fine-leaved plants (Java moss) or a spawning mop so eggs can fall into cover.
• Dim the light and consider some floating plants—bright lights tend to make them nervous.
• Condition adults for a week or two with frozen/live foods.
• After you see spawning activity, pull the adults or you’ll end up with zero eggs left.

6) Common problems to watch for

Most issues with hengeli are really “new tank” issues or stress issues. They’re hardy once settled, but they don’t love chaos.

• Pale color/hiding: usually not enough cover, too much light, too small a group, or they’re being intimidated by tankmates.
• Not eating well: food size is too large, or faster fish are stealing it.
• Ich after purchase: common on new fish when stressed—quarantine if you can, and don’t add them to a tank that’s already running warm and crowded.
• Wasting away over time: often internal parasites or chronic stress; watch for pinched bellies and isolate/treat if needed.
• Sudden losses: typically ammonia/nitrite spikes, poor acclimation, or a tank that isn’t fully cycled.