Dianchi stone loach

Where they come from

Dianchi stone loaches (Sphaerophysa dianchiensis) are from the Dianchi Lake drainage in Yunnan, China. Think cool, well-oxygenated water, lots of rock and gravel, and a life spent glued to the bottom picking at biofilm and tiny critters. They are not a "decorate the tank and forget it" kind of fish.

Setting up their tank

Build the tank around flow, oxygen, and a bottom that will not chew up their faces. I have had the best results treating them like a small river fish, not a "community bottom feeder".

• Tank size: I would not do less than a 20 gallon long footprint for a small group. More floor space beats more height every time.
• Substrate: smooth sand or very fine rounded gravel. Sharp gravel is a recipe for worn barbels and mouth damage.
• Hardscape: rounded river stones, cobbles, and a couple of tight crevices. They like to wedge themselves under and between rocks.
• Flow: strong. A canister filter with a spray bar plus a powerhead works well. You want current across the bottom, not just surface agitation.
• Oxygen: heavy aeration or a lot of surface movement. These loaches act weird fast if oxygen drops.
• Lighting: moderate. Too bright with no cover keeps them hiding all day.

Water-wise, think clean and on the cooler side of typical tropical. I kept mine happiest in the high 60s to low 70s F (around 20-23 C), with stable parameters and low nitrate. They do not like big temperature swings or a tank that gets "a little dirty" between water changes.

What to feed them

They are micro-predators and grazers. If you only toss in flakes, they will survive for a while and then slowly fade. The trick is getting food down to them in the flow and making sure they actually get their share.

• Staples: sinking micro pellets, small sinking wafers (broken up), and gel foods pressed onto rocks
• Frozen: bloodworms, blackworms, daphnia, cyclops, brine shrimp (better as a mixer than the main food)
• Live (great for conditioning): blackworms, whiteworms, live daphnia if you can get it clean
• Natural grazing: biofilm and aufwuchs off stones and wood (this is why a mature tank helps so much)

How they behave and who they get along with

These are bottom-focused, a little shy at first, and very much "my rock, my spot" with their own kind. You will see little shoves and short chases, especially around favorite hides, but in a tank with lots of broken lines of sight they sort it out.

• Best group size: 5-8 if your footprint allows. Singles tend to hide and stay tense.
• Good tankmates: other cool-water, current-loving fish that do not camp on the bottom (small danios, some barbs, stream-type minnows).
• Avoid: big boisterous fish, anything that bullies the bottom, and other territorial bottom loaches in tight quarters.
• Shrimp/snails: small shrimp may get picked off, especially babies. Snails are usually ignored unless a loach finds an easy meal.

Breeding tips

Breeding them in home tanks is not something I would call common. If it happens, its usually in mature, high-oxygen setups with seasonal cues. I would treat it like a long-term project, not a weekend goal.

• Start with a real group so you have both sexes (sexing is not straightforward until fish are mature).
• Run them cooler for part of the year, then do a gradual warm-up plus larger water changes to mimic seasonal shifts.
• Condition with lots of small live/frozen foods for a few weeks.
• Give spawning-type habitat: smooth gravel, tight rockwork, and high flow with plenty of oxygen.

Common problems to watch for

Most issues with this species trace back to three things: warm stagnant water, a tank that is too "new," or not enough food making it to the bottom. They look fine until they suddenly do not.

• Low oxygen: hanging in the flow, rapid breathing, acting frantic after lights-out. Fix with more surface movement, cooler temps, and less gunk in the filter.
• Barbel wear and mouth damage: usually from sharp substrate or dirty substrate. Swap to smooth sand and vacuum lightly but regularly.
• Slow starvation: hollow bellies, thin shoulders behind the head, fading energy. Increase feeding frequency and use sinking foods in the current.
• Sensitivity to meds: loaches can react badly to strong doses. If you must treat, research the drug and start low, with extra aeration.
• New fish crash: losses in the first 1-2 weeks from shipping stress and weak condition. Acclimate slowly, keep lights low, and feed small amounts more often.