W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<style>
  #frameDiv {
    width: 400px;
    height: 170px;
    margin: 20px;
    position: relative;
    border: solid black 1px;
    background-color: rgb(205, 242, 205);
  }

img {
    position: absolute;
    z-index: 1;
    width: 70px;
    offset: path('M 50 80 C 150 -20 250 180 350 80') 150px -90deg / 0% 50%;
    animation: moveImg 4s 1s 3;
  }

svg {
    position: absolute;
    height: 100%;
    width: 100%;
    left: 0;
    top: 0;
  }

@keyframes moveImg {
    100%  { offset-distance: 100%; }
  }
</style>
</head>
<body>

<h1>The offset property</h1>

<p><mark><strong>Note: </strong> Because this example uses 'offset-anchor' it currently only works with the Firefox browser.</mark></p>

<p>Here, the shorthand property 'offset' is used to set property values for offset-path, offset-distance, offset-rotate and offset-anchor:</p>
<ol>
  <li>The path for the animation is set (offset-path)</li>
  <li>the fish starts moving at a 150 pixels distance from the start of the path (offset-distance)</li>
  <li>the fish is rotated a constant -90 degrees (offset-rotate)</li>
  <li>the fish is connected to the path at the end of its tail, at the very left side of the element, 50% from the top (offset-anchor)</li>
</ol>

</body>
</html>