Hexi stone loach

Where they come from

Hexi stone loaches (Triplophysa hexiensis) come from cool, fast-moving streams in China. Think rocky runs, lots of oxygen, and water that stays pretty clean year-round. That background explains almost everything about how they act in a tank: they love current, they hug the bottom, and they are at their best in a setup that feels like a streambed.

Setting up their tank

Give them floor space and current before you worry about tall water volume. A long tank with a strong filter and a powerhead is way more useful than a tall cube. They spend most of their life cruising the bottom, wedging between stones, and surfing the flow.

• Tank size: I would start at 20 gallons long for a small group, bigger if you want to mix species
• Substrate: smooth sand or fine gravel (skip sharp stuff - they belly-scoot a lot)
• Hardscape: rounded river rocks, cobbles, and a few larger stones to break line of sight
• Hides: rock piles with tight gaps, driftwood caves, or small clay tubes
• Flow and filtration: strong turnover and directional flow; prefilter sponge helps if you have small tankmates
• Oxygen: an airstone or aggressive surface agitation makes a difference with these fish

Temperature-wise, they do best on the cooler side of tropical. Room-temp setups work well if your house is not roasting. What they hate is warm, stagnant water with low oxygen.

What to feed them

These are bottom feeders with a taste for meaty foods, not algae grazers like some people assume from the name. Mine did best on a mix of sinking prepared foods plus frozen/live stuff. If they are only picking at biofilm, they usually get skinny over time.

• Daily staples: sinking micro pellets, small sinking wafers, bottom-feeder granules
• Frozen: bloodworms, daphnia, brine shrimp, mysis (chopped if pieces are big)
• Live (if you can get it): blackworms, grindal worms, live daphnia
• Occasional: repashy-style gel foods (great for getting calories into a shy group)

Feed after lights out sometimes. They are not strictly nocturnal, but they get bolder in dim light, and that is when the shy ones actually eat. If you keep them with fast midwater fish, you will need to target-feed the bottom.

How they behave and who they get along with

Hexi stone loaches are busy little bottom cruisers with a mild attitude most of the time. You will see short bursts of chasing and posturing, especially if you keep just one or two. In a group, the sparring is spread out and they settle into a pecking order.

• Best kept: small group (I like 5+ if the tank footprint allows)
• Good tankmates: cool-water danios, small barbs, white cloud mountain minnows, calmer minnows, other streamy fish that like flow
• Also works with: some hillstream loaches and small rheophilic catfish, as long as there are enough hides
• Avoid: slow fancy fish, long-finned fish, warm-water species, and super territorial bottom dwellers

They are not usually fin-nippers, but they can annoy slow fish by constantly being underfoot. With other bottom fish, the key is lots of cover and multiple feeding zones. If there is only one prime cave, somebody will claim it.

Breeding tips

Breeding Triplophysa in home tanks is possible but not something I would call predictable. If you want to try, think like the seasons: cooler period, then a bump in temperature and lots of fresh water changes that mimic spring melt.

• Keep a group with both sexes (sexing is subtle until they mature)
• Strong flow and lots of oxygen seem to matter
• Heavy feeding on live/frozen foods for a few weeks helps condition them
• Try large, frequent water changes with slightly cooler water, then slowly warm back up
• Provide spawning sites like pebble beds, tight rock gaps, or a coarse gravel tray you can lift out

If eggs or fry show up, adults may snack on them. A removable spawning tray or a separate breeding setup gives you a better shot. Fry will want tiny live foods early on, like microworms and baby brine, plus infusoria/biofilm in a mature tank.

Common problems to watch for

Most issues I have seen with stone loaches come down to two things: low oxygen and not enough food making it to the bottom. They can look fine for weeks, then slowly waste away if they are always losing meals.

• Skinny fish despite feeding: food competition, too much current blowing food away, or internal parasites (especially in new imports)
• Gasping or hanging in high flow: oxygen is low, temp is too warm, or the tank is dirty
• Constant hiding and stress colors: not enough cover, too bright, or aggressive tankmates
• Scrapes and torn fins: sharp rocks, rough decor, or too-tight quarrels over one hide
• Ich and other spot diseases: often triggered by stress from shipping and warm temps

The best day-to-day habit is simple: keep the water clean and moving, and make sure every fish gets to eat. If you do those two things, Hexi stone loaches are hardy and really fun to watch once they settle in.