Blacktip rasbora
Rasbora dorsinotata
The Blacktip rasbora features a slender body with a prominent black stripe along the dorsal fin and a silvery-grey coloration.
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About the Blacktip rasbora
This is a slim little Southeast Asian rasbora with a clean dark lateral stripe and a neat black tip on the dorsal fin. In a group it gets way more confident and you will see that tight midwater schooling behavior, especially in a planted tank with some flow.
Quick Facts
Size
4.3 cm SL
Temperament
Peaceful
Difficulty
Intermediate
Min Tank Size
20 gallons
Lifespan
3-5 years
Origin
Southeast Asia
Diet
Omnivore/insectivore leaning - small pellets/flake plus frozen/live foods (daphnia, bloodworms, etc.)
Water Parameters
20-25°C
6-7.5
2-12 dGH
Need a heater for this species?
This species needs 20-25°C in a 20 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Keep them in a proper group (8-12+). In small numbers they get jumpy, hide a lot, and the nipping goes up.
- They look best and act calmer in a long tank with open swimming room plus plants along the sides (fine-leaf stuff is great). Toss in some floating plants to dim the light and they color up.
- Aim for soft to moderately soft water and slightly acidic to neutral pH (about 6.0-7.2), and keep temp around 75-80F. They really hate big swings, so do smaller, regular water changes instead of random big ones.
- Feed small foods they can grab midwater: micro pellets, crushed flakes, baby brine, daphnia, cyclops. Two small feedings beats one big dump - they are quick, but leftovers will wreck the tank fast.
- Good tankmates are other chill SE Asian community fish that like similar water: small rasboras, peaceful barbs, kuhli loaches, small gouramis, and shrimp that are not tiny babies. Skip fin-nippers and anything big-mouthed like adult angels or most aggressive barbs.
- They are jumpers, especially when spooked, so use a lid and block any gaps around filter hoses. Sudden lights-on also makes them rocket, so ramp the room light first or use floaters.
- Breeding is doable if you give them a separate tank with soft water and a mesh/marbles or a thick clump of moss since they will eat eggs. Condition with live/frozen foods, then pull the adults after a spawn and start the fry on infusoria/microworms before baby brine.
- Watch for skinny fish and clamped fins after new arrivals - they can come in with internal parasites or just stress out easily. Quarantine if you can, and keep the main tank well-oxygenated because they sulk fast in warm, low-flow water.
Compatibility
Good Tankmates
- Other small, chill schooling fish like harlequin rasboras or lambchop rasboras - they have the same vibe, stay midwater, and nobody gets pushy
- Small tetras that are more polite than bitey (neon, ember, glowlight) - they cruise around together and blacktips do not get stressed out by them
- Peaceful bottom crews like corydoras (pandas, peppers, sterbai) - different level of the tank, zero drama, and corys do not bother the rasboras at all
- Kuhli loaches - nocturnal noodle gang that keeps to itself, and the rasboras just ignore them
- Otocinclus - great little algae grazers, super non-threatening, and they do not compete much for food if you feed properly
- Honey gourami (or other gentle small gourami) - works well if the tank is not cramped and you have plants so everybody can claim a little space
Avoid
- Fin-nippers and rowdy semi-aggressive stuff like tiger barbs - they will hassle the rasboras and keep them hiding instead of schooling
- Big mouthy fish that see small rasboras as snacks (most medium-large cichlids, larger gouramis) - if it can fit them in its mouth, it eventually will
- Aggressive bettas or other territorial labyrinth fish in tight setups - some are fine, but the bad ones will chase and stress the whole school
Where they come from
Blacktip rasboras (Rasbora dorsinotata) are Southeast Asian little stream fish. You will mostly see them associated with clear to slightly tea-colored forest waters with lots of plants and leaf litter. That background explains a lot about what makes them settle in: cover overhead, calm flow, and water that is not rock-hard.
They can look a bit washed out in bare, bright tanks. Give them plants and darker decor and the black dorsal tip and overall color pop way more.
Setting up their tank
Think small schooling fish that want to feel hidden, not trapped. A longer footprint beats a tall tank. I would start them in a 20 long style setup if you can, but a well-planted 15-20 gallon works great for a proper group.
- Group size: 8-12+ (they act way calmer and show better color in numbers)
- Temp: mid 70s F is a sweet spot (around 74-78F)
- pH: slightly acidic to neutral is easiest (roughly 6.0-7.2)
- Hardness: soft to moderate; avoid super hard water if you can
- Filtration: gentle flow, lots of bio (sponge or a baffled HOB works well)
- Lighting: medium; floating plants help a ton
Decor-wise, you cannot really overdo plants with these. I like a mix of stem plants for cover, a clump or two of java fern or crypts, and some floaters. A darker substrate and a couple pieces of wood make them feel like they have "edges" to hang around.
If your rasboras are hiding constantly, add more overhead cover (floaters or tall plants) before you start chasing water numbers. That alone often fixes it.
What to feed them
They are easy to feed once you remember their mouths are small. Mine did best with tiny foods offered more like "snacks" than one big dump. They are little pickers in the water column.
- Daily staple: fine micro pellets or crushed flake
- Best conditioning foods: baby brine shrimp, daphnia, cyclops
- Frozen options: frozen baby brine, small-size mysis (chopped if needed)
- Occasional: grindal worms or microworms (great for getting shy fish eating)
Skip big pellets. If food hits the bottom untouched, it just rots and you get algae and grumpy fish. Go smaller, feed lighter, and watch their bellies.
How they behave and who they get along with
Blacktip rasboras are classic peaceful schoolers. They will do little sparring displays with each other (no damage, just posturing), then go right back to cruising as a group. If you only keep 3-4, they get twitchy and fade into the plants.
- Great tankmates: other small rasboras, peaceful tetras, corydoras, otocinclus, small loaches, shrimp (adults usually fine)
- Use caution with: long-finned slow fish (not because they are mean, but busy schools can stress them)
- Avoid: big semi-aggressive fish, fin nippers, anything that sees 1 inch fish as food
They look best with other calm midwater fish and a quiet bottom crew. In a community, give them the middle lane and plenty of line-of-sight breaks so they do not feel exposed.
Breeding tips
They are egg scatterers, and the adults will happily snack on eggs and tiny fry if they find them. Spawning is doable, but you will have a much better time if you set up a separate small breeding tank rather than hoping for survivors in the display.
- Breeding tank: 5-10 gallons, sponge filter, heater, dim light
- Spawning trigger: heavy feeding with live/frozen for a week, then a slightly cooler water change
- Spawning media: a big clump of java moss, spawning mop, or a mesh/egg crate barrier so eggs drop out of reach
- After spawning: pull the adults the same day if you can
- First foods: infusoria or powdered fry food, then baby brine shrimp once they are big enough
If you see them doing quick little chases and "shivering" in the plants early in the day, that is often the start of spawning behavior. That is your cue to check the moss/mesh and consider removing adults.
Common problems to watch for
Most issues I have seen with these come from stress, shipping, and tanks that are too bare or too small for a real group. They are not fragile, but they do not forgive messy water and sudden swings.
- Faded color and hiding: usually too few fish, too much light, not enough plant cover, or they feel outcompeted at feeding time
- Ich/white spot after purchase: common if they were stressed in transit; quarantine helps a lot
- Wasting away: can be internal parasites or just not getting enough food (tiny mouths in a fast community)
- Clamped fins and hovering: check ammonia/nitrite, then look at temperature swings and aggressive tankmates
- Jumping: they can hop when startled, especially during the first week
Use a lid. I have lost small rasboras through tiny gaps around airline tubing. If there is a gap, they will find it on the one night you forget.
If you are troubleshooting, start with the basics: stable temp, clean water, and a bigger group. Then make sure they actually get food. In a busy community tank, I like to feed a tiny pinch, wait 30 seconds, then feed again so the shy ones get a turn.
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