[en] The decay properties of ¹⁵⁵Lu, ¹⁵⁵Yb, ¹⁵⁵Tm, and of the α-decay daughters ¹⁵¹Er and ¹⁵¹Ho were investigated following the on-line mass separation of A=155 nuclides produced in ⁶⁴Zn irradiations of ⁹⁵Mo. In the study, the half-life of the low-spin isomer in ¹⁵⁵Lu was measured to be 140±20 ms, the β-decay branch of ¹⁵⁵Yb was identified by observing daughter γ rays and Tm K x rays, and the existence in ¹⁵⁵Tm of an s_1/2 isomer (T_1/2=44±4 s), in addition to the h_11/2 ground state (T_1/2=21.6±0.2 s) was established. Schemes for the β decays of ¹⁵⁵Yb, ¹⁵⁵Tm, and ¹⁵¹Er are proposed. New information on ¹⁵¹Er decay establishes the s_1/2 isomer in ¹⁵¹Ho to be 41.1±0.2 keV above the h_11/2 ground state. Also, branchings of 90±5, 28±7, and 80_-20⁺¹⁵% were determined for the α decays of ¹⁵⁵Yb, ¹⁵¹Ho, and ¹⁵¹Ho^m, respectively