Colour aberration

[NautilusCairns]

What causes unexpected coluration especially wheren there is a strong contrast? For example a blue colour on the edge of the white stripes on a clown fish or a green colour on the edge of a golden damsel fish. Is it to do with the quality of the lens? I am using a Canon A640 in an Ikelite housing with an Ikelite DS51 strobe.

 

[MauiScubaSteve]

I had both a Canon S90 and a Olympus c5050z when I was shooting resort guest dives, and I saw similar blemishes on the Canon images.

The Oly had superior glass, and a larger sensor, so I chalked it up to the cheaper stuff used to make the Canon.