Purple Fin Hillstream Loach (Pseudogastromyzon laticeps)

<h2>Common Name</h2>
<p>Purple Fin Hillstream Loach. You may also see Purple Fin Sucker or Rainbow Hillstream Loach depending on the importer.</p>

<h2>Origin and Habitat</h2>
<p>This species is native to coastal mountain stream systems in Guangdong Province, China, and is reported as endemic to the Longjin He drainage. It is adapted to shallow riffles and runs with clear water, strong current, and very high dissolved oxygen.</p>

<h2>Biotope and Compatible Species</h2>
<p>A realistic biotope look is smooth stones, rounded gravel, cobble, and boulders with strong current and lots of oxygen. In the highest flow zones, the main food and cover is periphyton and biofilm coating the rocks. True plants tend to be limited to calmer margins and sheltered pockets.</p>

<p>Aquarium friendly tankmates that usually work well in the same style of setup, meaning peaceful and able to handle current, include:</p>
<ul>
  <li>White Cloud Mountain Minnows (<em>Tanichthys albonubes</em>)</li>
  <li>Small danios that enjoy current, such as Zebra Danios and similar <em>Danio</em> species</li>
  <li>Other gentle hillstream loaches and stream loaches when there is enough rock territory for everyone</li>
  <li>Freshwater shrimp and snails, especially in mature tanks with established biofilm</li>
</ul>

<p>If you want a planted look, keep plants to calmer pockets and behind rockwork. Vallisneria and hornwort are good choices when placed out of the main current lane.</p>

<h2>Temperature and Water Conditions</h2>
<p>They do best in cool to mildly warm water with very high oxygen. Aim for clean water, strong flow, and heavy aeration. Stability matters more than chasing a perfect number.</p>
<ul>
  <li>Temperature: 18 to 24 C, 64 to 75 F</li>
  <li>pH: about 6.5 to 7.5 works well for most setups</li>
  <li>Ammonia and nitrite: zero, nitrate kept low through routine maintenance</li>
</ul>

<h2>Appearance and Size</h2>
<p>Flattened body, wide pectoral fins, and a suction adapted underside that lets them hold position on rock and glass in strong current. In good condition, the fins can show attractive purple to magenta tones, especially under strong lighting and high oxygen.</p>
<p>Maximum size is reported around 6.7 cm standard length, about 2.6 inches, though many aquarium fish stay a bit smaller.</p>

<h2>Diet in the Wild</h2>
<p>They are specialised grazers. In nature they spend most of the day rasping biofilm and periphyton from rock surfaces, along with tiny micro invertebrates living in that film.</p>

<h2>Feeding in Captivity</h2>
<p>Treat them like nonstop grazers that still appreciate variety. Offer a mix of algae and biofilm oriented foods plus occasional small protein.</p>
<ul>
  <li>Algae wafers and spirulina based foods</li>
  <li>Gel foods such as Repashy style diets</li>
  <li>Blanched zucchini, cucumber, and spinach</li>
  <li>Frozen daphnia, cyclops, and baby brine shrimp, with bloodworms only as an occasional treat</li>
</ul>

<p>Mature surfaces matter. A brand new sterile tank often has nothing for them to do except pace the glass like they are looking for the manager.</p>

<h2>Behavior and Tank Setup</h2>
<p>Generally peaceful, active, and mildly territorial with their own kind over the best grazing spots. They do well in small groups when the tank provides enough rock surface and multiple feeding areas.</p>
<ul>
  <li>Smooth rocks and rounded stones for grazing surfaces</li>
  <li>High flow lanes plus calm breaks behind rockwork</li>
  <li>High oxygen all the time, especially if the tank runs warmer</li>
  <li>A tight lid is smart, hillstream loaches can climb glass</li>
</ul>

<h2>Breeding</h2>
<p>Breeding is possible but not guaranteed. Spawning activity often increases after a period of strong feeding followed by a cooler, larger water change. Eggs are typically placed near rockwork or in areas where they can settle into crevices and stay protected.</p>

<h2>Breeder’s Tips</h2>
<ul>
  <li>Keep a group so you have better odds of mixed sexes and natural social triggers</li>
  <li>Build rock piles with tight gaps so eggs can fall into safety</li>
  <li>Trigger with a big cool water change after a week of strong feeding</li>
  <li>If fry appear, start with tiny foods, then move to baby brine shrimp as they grow</li>
  <li>Do frequent small water changes, keep oxygen very high, and avoid stripping every surface clean at once</li>
</ul>

<h2>Quick Facts</h2>
<ul>
  <li>Scientific name: <em>Pseudogastromyzon laticeps</em></li>
  <li>Adult size: about 2.5 inches, maximum reported around 2.6 inches standard length</li>
  <li>Temperament: peaceful, mildly territorial with its own kind</li>
  <li>Best setup: high flow river style tank with lots of rock surfaces</li>
  <li>Feeding style: biofilm grazer with an omnivorous lean</li>
  <li>IUCN Red List status: Near Threatened, assessed June 18, 2023</li>
</ul>

<h2>Tropical Fish Co. Notes</h2>
<p>Hillstream loaches are Jodi’s favorite. All of them. Not one of them, not most of them, all of them. If hillstream loaches had a fan club, she would be the president, the treasurer, and the person politely asking you to add more flow.</p>
<p>Purple fin hillstreams are a perfect example of the obsession. They spend their day doing extreme sports on rocks, eating invisible snacks, and acting like the filter output is a scenic overlook. Give them oxygen, current, and mature surfaces, and they will stay busy all day while pretending your aquarium glass is a climbing wall.</p>