Brown forktail loach
Vaillantella cinnamomea
The Brown forktail loach features a slender, elongated body with a distinct yellow-brown coloration and forked caudal fin.
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About the Brown forktail loach
Vaillantella cinnamomea is a slim little Borneo loach with that cool forked tail and a subtle cinnamon-brown body with a dark eye stripe. It spends most of its time hugging the bottom and weaving through leaf litter and roots, then suddenly darts like a tiny torpedo when food hits the sand. Keep the tank covered tight - these forktails are famous for surprise launches.
Also known as
Quick Facts
Size
5 cm
Temperament
Peaceful
Difficulty
Intermediate
Min Tank Size
20 gallons
Lifespan
5-8 years
Origin
Southeast Asia (Borneo, Indonesia - East Kalimantan/Mahakam basin)
Diet
Omnivore - small sinking foods, frozen/live (daphnia, brine shrimp, cyclops), micropellets
Water Parameters
22-26°C
6-7
2-10 dGH
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Calculate heater sizeCare Notes
- Give them a long tank with lots of cover - sand or smooth fine gravel, rounded rocks, wood, and leaf litter. They like to wedge into tight spots, so build a few caves and crevices.
- They do best in cooler-to-mid temps (around 22-26 C / 72-79 F) with decent flow and high oxygen, like a river setup. Keep ammonia and nitrite at zero and don't let nitrate creep up if you want them active and chunky.
- They are shy at first, so keep lighting low and add plants or floaters to break it up. If the tank is bare and bright, you'll basically never see them.
- Feed like a bottom predator, not an algae eater - sinking carnivore pellets, frozen bloodworms, blackworms, brine shrimp, and chopped earthworms. Drop food after lights-out sometimes because they get bolder in the evening.
- They do better in a small group (3-6) so one fish isn't getting all the stress. Expect some harmless shoving for spots, but real damage usually means the tank is too cramped or there are not enough hides.
- Good tankmates are calm midwater fish that like similar temps and clean water - small barbs, rasboras, danios, and peaceful loaches. Skip fin-nippers and anything big and pushy (or predators) because these guys are timid and get outcompeted at feeding time.
- Watch for skinny bellies and hollow flanks - that's usually not eating enough, internal parasites, or getting bullied off food. Also avoid sharp decor because they scrape themselves when they dart into caves.
- Breeding in home tanks is rare; if it happens it's usually in a mature, heavily structured tank with lots of microfood and stable conditions. If you ever see tiny fry, feed infusoria or powdered fry food first, then baby brine shrimp once they can take it.
Compatibility
Good Tankmates
- Small, chill schooling fish like rasboras (harlequins, hengeli/espei) - they hang midwater, stay polite, and dont bother a shy loach cruising the bottom
- Peaceful tetras that arent fin-nippy (ember, glowlight, rummy-nose) - good movement up top without turning the tank into a stress-fest
- Calm gouramis like honey gourami - gentle personality and they usually ignore bottom fish, so the loach can do its own thing
- Other peaceful bottom dwellers like Corydoras - they share the floor pretty well as long as theres enough sand and hiding spots for everyone
- Small, non-bossy catfish like Otocinclus - they keep to themselves and dont compete hard for territory
- Peaceful dwarf cichlids like Apistogramma (in a roomy, well-decorated tank) - generally fine if the cichlids arent in full-on breeding defense mode
Avoid
- Fin-nippers like tiger barbs or serpae tetras - they can harass anything calm, and the loach will spend all day hiding
- Big, pushy semi-aggressive fish like larger cichlids (convicts, most mbuna) - too much aggression and too much territory drama for a peaceful loach
- Fast, food-bullying loaches like clown loaches or big Botia types - they tend to outcompete at feeding time and can rough up calmer bottom fish
- Anything that treats small bottom fish like snacks (bichirs, big leaf fish, larger predatory catfish) - even if they seem chill, the risk is real as they grow
Where they come from
Brown forktail loaches (Vaillantella cinnamomea) come from blackwater and forest streams in Southeast Asia (think leaf litter, tannins, and soft, tea-colored water). They are built for poking around in tight spots and cruising along the bottom in gentle current.
The vibe in their natural habitat is pretty consistent: warm, shaded, lots of hiding places, and not a ton of harsh light. If you copy that feel, they settle in way faster.
Setting up their tank
These loaches do best in a tank that gives them cover and a reason to explore. You will see a completely different fish if they have wood, plants, and leaf litter to work through instead of a bare setup.
- Tank size: 20 gallons long works for a small group, bigger is easier for stability and reduces squabbles
- Substrate: fine sand or very smooth small gravel (they spend a lot of time nose-down)
- Hardscape: driftwood roots, rock piles with gaps, and a couple of cave-like hides
- Botanicals: Indian almond leaves, oak/beech leaves (if safe), alder cones for that blackwater feel
- Plants: low light plants and floating plants help them feel secure
- Flow and filtration: decent bio-filtration and gentle-to-moderate flow, plus high oxygen
Give them multiple hides with more than one entrance. If a dominant fish decides a cave is "the" cave, having extra exits keeps the weaker fish from getting pinned.
For water, think soft to moderately soft, slightly acidic to neutral, and clean. They are not the kind of loach that tolerates dirty, low-oxygen setups for long. Regular water changes make a bigger difference with this species than chasing a specific pH number.
They can wedge into surprisingly small gaps. Cover filter intakes, block off tiny holes behind hardscape, and use a lid. If there is a way out, they will eventually find it.
What to feed them
They are enthusiastic little predators and scavengers. Mine acted shy the first week, then turned into fearless dinner seekers once they learned the schedule.
- Staples: sinking wafers and quality micro pellets that hit the bottom fast
- Frozen: bloodworms, brine shrimp, daphnia, mysis (mix it up)
- Live (great for conditioning): blackworms, live brine, grindal worms
- Occasional: chopped earthworm if you have bigger individuals
Feed after lights-out sometimes. They will still come out during the day once settled, but evening feeding helps shyer fish get their share, especially if you keep faster midwater fish.
I like to scatter food across the bottom instead of dropping one big pile. It spreads them out and cuts down on little spats.
How they behave and who they get along with
They are more social than people expect. In a group they are bolder, and you will see those quick little dashes and bottom patrols. Solo individuals can turn into a permanent ghost fish.
- Best group size: 5+ if you can swing it (3 is workable, but you will see more pecking order stuff)
- Temperament: generally peaceful, but they will posture and chase over favorite hides
- Activity: crepuscular at first (more active at dusk), then often day-active once comfortable
Tankmates should be calm and not obsessed with the bottom. Think small rasboras, peaceful barbs, pencilfish, or other gentle midwater fish. Avoid hyper food hogs if you do not want to babysit feeding.
They usually ignore shrimp, but tiny baby shrimp are always a gamble with any bottom prowler. If you care about maximizing shrimplet survival, pack the tank with moss and fine plants.
Breeding tips
Breeding them in home aquariums is possible but not something most people stumble into by accident. If you want to take a run at it, conditioning and setup details matter more than anything fancy.
- Start with a group and let them mature together
- Condition with lots of live/frozen foods for a few weeks
- Keep water very clean with frequent changes
- Try a seasonal cue: slightly cooler water changes and then back to warm, along with heavier feeding
- Use a mature tank with leaf litter and tight hides; a sponge filter helps keep fry-safe flow
If you do get eggs or fry, assume the adults will snack if they find them. A separate breeding tank or egg-safe structure (dense plants, leaf litter, crevices) makes a big difference.
Common problems to watch for
Most issues I have seen with these guys come down to stress from a too-bright, too-bare tank, or from being kept in a pair or solo. They are tougher than their shy behavior suggests, but they do not love sloppy water.
- Hiding constantly: usually not enough cover, too much light, or too few loaches
- Scraped barbels or mouth: sharp gravel/rocks, or dirty substrate that needs better maintenance
- Fast breathing: low oxygen or gunked-up filtration (they like well-oxygenated water)
- Sunken belly: not getting enough food in a busy community tank, or internal parasites in new imports
- Odd daytime aggression: too few hides or a cramped footprint
Be cautious with medications, especially copper-based ones. Loaches can be touchy. If you have to treat, start low, increase aeration, and watch them closely.
The best "fix" is usually preventative: a mature tank, lots of cover, steady maintenance, and feeding in a way that lets the shy fish eat. Once they feel secure, they are honestly a joy to watch.
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