Erromyzon sp. 'ER01'

Overview

Erromyzon sp. 'ER01' is an unidentified hillstream loach requiring a stable, oxygenated aquarium with extensive grazing surfaces. Clean circulating water and established growth on rocks matter more than an elaborate decorative layout.

Distribution & habitat

Its range has not been verified. Arrival among imported Beaufortia kweichowensis suggests an origin in southern China's Xi Jiang, within the Pearl drainage.

Members of the genus inhabit shallow, rapidly flowing headwaters and tributaries over sand, gravel, and rocks. Clear, oxygen-rich water and sunlight support extensive biofilm. These conditions describe the genus and are not a documented collection site for ER01.

Aquarium setup

Use a base of roughly 60 × 30 cm or larger. Rounded stones of different sizes can cover sand or gravel. Strong filtration, supplementary circulation, and aeration should keep the water clean and oxygenated; a suggested turnover is ten to fifteen tank volumes each hour.

Bright lighting encourages food-producing growth. Weathered wood is usable, whereas heavy staining from fresh wood can reduce useful light. Hardy plants offer cover and extra surfaces. Exposed sponge filters may also be grazed.

The aquarium must already be biologically stable. Maintain regular partial water changes while retaining growth on most surfaces. A tight cover is required because the fish can climb the glass.

Diet & feeding

Algae and associated microscopic life are presumed to dominate the wild diet. Prepared foods and bloodworms are accepted in captivity, but excessive protein may cause internal problems.

Vegetable-rich gel foods can supplement continuous access to mature grazing surfaces. If growth is insufficient, cultivate algae on stones in a separate brightly lit container and rotate them into the aquarium. Soft green algae and diatoms are more useful than tough brush algae. Severely thin arrivals need uninterrupted suitable food without competition during recovery.

Behaviour & compatibility

Usually peaceful, it can share space with suitable stream fishes. Mild territoriality occurs among conspecifics, yet a group of at least four is recommended. Minor disputes with other hillstream loaches are also possible.

Sexual dimorphism

Larger, deeper-bodied fish may be females, but this guide lacks confirmed documentation.

Breeding

Captive spawning has not been recorded for ER01. Reproduction of the unidentified ER02 involved eggs placed in gravel and young initially hiding below the surface. That observation provides comparative context rather than a verified method for this fish.

Notes

Resemblance to Erromyzon yangi has been noted, without establishing identity. The ER code is a temporary way to separate unresolved records.