Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 43: Gaṅgā Descends to the Earth
Text 1.43.20

मत्स्यकच्छपसङ्घैश्च शिंशुमारगणैस्तदा।
पतद्भिः पतितैश्चान्यैर्व्यरोचत वसुन्धरा॥

matsya-kacchapa-saṅghaiś ca śiṁśumāra-gaṇais tadā
patadbhiḥ
patitaiś cānyair vyarocata vasundharā

matsya-kacchapa-saṅghaiḥ ca = with fish, tortoises; śiṁśumāra-gaṇaiḥ = porpoises; patadbhiḥ patitaiḥ ca anyaiḥ = and other aquatics that were falling and that had fallen [into its waters]; vyarocata = then shone; vasundharā = the earth.

Then, the earth shone with fish, tortoises, porpoises and other aquatics that were falling and that had fallen [into its waters].

Śiṁśumāra is also called ambu-kapi, according to Vaijayantī.