Hello,

Please try adding the following Custom CSS for that.

.single-product .wd-carousel-container .wd-action-btn.wd-style-icon>a:hover:before {
    color: #808080;
}

.single-product .wd-carousel-container .wd-action-btn.wd-style-icon>a:hover:before {
    color: green;
}

Regards.
Xtemos Studios