The ultrastructure of the egg chorion surface in the loach Misgurnus anguillicaudatus was investigated using scanning electron microscopy (SEM). A single micropyle, which belonged to type II, was found at the animal pole of an M. anguillicaudatus egg. Several sinistral grooves which originated at the micropyle probably served for sperm guidance. The egg envelope had numerous pores with bud-like fillings and a regular arrangement like honeycomb. Lots of small knobs were situated on the zona radiata at the vegetal pole. Water contact triggered egg stickiness within about 10 seconds. The egg surface became smooth after treatment with trypsin solution. The features of the micropyle, pores and stickiness were correlated with the reproductive strategy of the loach and are important for egg identification.