30 Piscium (HIP 154) is a solitary variable star in the zodiac constellation of Pisces. It is visible to the naked eye with an apparent visual magnitude of 4.37. Its calculated mid-value of antiposed parallax shift as the Earth moves around the Sun of very roughly 7.88 mas, makes it around 410 light years away. Its net movement in the present epoch is one of moving closer – radial velocity (speed away from our star system) is −12 km/s.

This is an aging red giant star with a stellar classification of M3 III, indicating it has exhausted the hydrogen at its core and evolved off the main sequence. It is a candidate long-period variable star and has been given the designation YY Psc. It varies in brightness between magnitudes 4.31 and 4.41 with no clear period. Possible periods of 23.1, 32.0, 53.6, and 167.8 days have been identified. The star has 109 times the Sun's radius and is radiating 1,600 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,490 K.