Something like these? 10-pack RGB colour lights with remote, UK and US links below but I bet there’s equivalents for other markets/countries…

UK= https://www.amazon.co.uk/Submersible-Waterproof-Flameless-Underwater-Halloween/dp/B097XWJZQ4?pd_rd_w=OLdkO&content-id=amzn1.sym.2e57bb8f-b34e-49d4-b4b6-f04b7a61e826&pf_rd_p=2e57bb8f-b34e-49d4-b4b6-f04b7a61e826&pf_rd_r=WK2RQCEMNC8ASRFFKXAJ&pd_rd_wg=ZqAz5&pd_rd_r=babcfc9e-c2a0-4ee4-842f-2403fd3767c2&pd_rd_i=B097XWJZQ4&psc=1&ref_=pd_bap_m_rp_aisle_ttr_7_t

US = https://www.amazon.com/Underwater-Submersible-Multicolor-Waterproof-Flameless/dp/B07MYTZT48/ref=mp_s_a_1_12?crid=2DPE2JF9A23FW&keywords=rgb+battery+light&qid=1664836703&qu=eyJxc2MiOiI0LjczIiwicXNhIjoiMy4yNCIsInFzcCI6IjMuNDQifQ%3D%3D&sprefix=rgb+baterry+light%2Caps%2C207&sr=8-12