Long-dorsal Yasuhikotakia (no established common name)

Where they come from

Yasuhikotakia longidorsalis is one of those river loaches that makes you wonder why it is not more common in the hobby. It comes from flowing freshwater in Southeast Asia (think moving water, rocks, sand, leaf litter, and a lot of oxygen). That background explains almost everything about how it acts in a tank: it likes current, it likes to graze, and it gets bored fast in a sterile setup.

Setting up their tank

Give them space and structure. These are active, bottom-focused fish that spend a lot of time cruising, poking into gaps, and doing quick little sprints. A long footprint beats a tall tank every time.

• Tank size: I would not keep a group in anything under a 4 foot tank. Bigger makes them calmer and way more fun to watch.
• Group size: aim for 5-6+ if you can. Singles and pairs tend to act edgy and pickier about tankmates.
• Substrate: sand or smooth fine gravel. They root around and will scrape themselves up on sharp stuff.
• Hardscape: rounded river stones, driftwood, and lots of hidey holes. Think caves and crevices they can duck into fast.
• Flow and oxygen: a strong filter plus extra circulation (powerhead or a good spraybar) makes a noticeable difference in activity and appetite.
• Lighting and plants: they do fine either way, but they appreciate shaded areas. Plants attached to wood/rock (Java fern, anubias, buce) hold up better than delicate stems getting bulldozed.

Water-wise, I have had the best luck keeping them in the middle ground rather than chasing extremes: neutral-ish pH, moderate hardness, and clean water with steady temps. What they react to more than numbers is sloppy maintenance. If nitrates creep up or mulm builds in dead spots, you will see it in their behavior and barbels.

What to feed them

They are classic loach eaters: not picky once settled, but they do best with variety. Mine spent a lot of time grazing and then hit meals hard when food drops.

• Staples: sinking pellets and wafers (rotate brands/sizes so you are not feeding the same formula forever).
• Frozen: bloodworms, brine shrimp, daphnia, and chopped krill. I like feeding frozen a few times a week to keep them in good weight.
• Live (if you do it): blackworms or live brine shrimp are great for conditioning and getting shy newcomers eating.
• Extras: blanched zucchini/cucumber or a bit of gel food now and then. Not every loach goes nuts for veg, but it is worth trying.

Feed after lights down sometimes. They will eat in daylight, but in a busy community tank they can get outcompeted by faster midwater fish. A second small feeding later in the day keeps everyone from turning into a skinny, grumpy loach.

How they behave and who they get along with

Expect personality. In a group they do the usual loach stuff: chasing, clicking, playful shoving, and a pecking order that looks dramatic but usually is not real damage. They also do that loach thing where they vanish all day and then suddenly everyone is out doing laps.

• Good tankmates: sturdy, peaceful schooling fish that like flow (danios, larger rasboras), rainbowfish, peaceful barbs, and other robust bottom fish that will not be bullied off food.
• Use caution: slow long-finned fish (they can get stressed by the commotion), very timid fish, and very small shrimp that might become snacks.
• Avoid: aggressive cichlids and anything that claims caves and fights for them.

Breeding tips

If you are hoping to breed them at home, set expectations: Yasuhikotakia species are not the easiest spawners in typical home setups, and a lot of "success" stories in the trade involve hormones. That said, you can still condition them and sometimes see spawning behavior.

• Keep a real group and let them mature. Odd numbers seem to spread the chasing out.
• Heavy conditioning with frozen/live foods for a few weeks helps a lot.
• Big water changes with slightly cooler water and strong flow can trigger extra activity (think rainy season).
• If you ever see eggs, they will not guard them. Adults will snack on them, so a separate setup or egg-safe barrier is needed.

Common problems to watch for

Most issues I have seen with these loaches trace back to three things: not enough group size, not enough oxygen/flow, or a tank that is not as clean as it looks.

• Skinny fish that never fill out: usually getting outcompeted at feeding time or not settled yet. Try night feeding and more sinking foods spread across the tank.
• Barbel wear or sore mouths: often from sharp substrate, dirty bottom areas, or both. Switch to sand/smooth gravel and vacuum dead spots.
• Ich and other parasites: loaches can be sensitive to meds and sudden changes. Quarantine new fish if you can, and raise temp slowly if you are using heat as part of treatment.
• Jumping or carpet surfing: they can launch when spooked, especially in a new tank. A tight lid saves lives.
• Odd hiding and heavy breathing: check flow, surface agitation, and temperature first. These fish act "off" fast if oxygen drops.