Good idea. I saw a similar idea used by the Artis Zoo when I visited the fish facilities back in 2010. There, the floating balls were made of polystyrene, and they were used to insulate from heat loss.
Dr Richmond Loh
DipProjMgt, BSc, BVMS, MPhil (Pathology), MANZCVS (Aquatics& Pathobiology), CertAqV, NATA Signatory.
THE FISH VET, Perth, Western Australia, AUSTRALIA.
Mobile Aquatic Veterinary Medical & Diagnostic Services.
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