Either class it as the depressing level of piracy on the PC, or else the over-draconian software publishers at work, but do we really need to have a registration code to enter on a £10 PC aquarium title? This is, after all, a title that does little more than push fish around a screen - admittedly in excellent style - and we're still fiddling with a case-sensitive code to get it working. Please, give us a break.

Blue Planet 3D Aquarium is an application that can run as a screensaver, standalone application or active desktop. As the name suggests, it's a virtual rendition of a very impressive fish tank and as plenty of people have been using such screensavers on their PCs for years, you can see some appeal to it.

We tried all three and warmed most to the active desktop. This, if you're unfamiliar with it, turns your working desktop into said virtual aquarium, while you carry on using your computer. You can choose between three underwater regions, enjoy the 26 different creatures bundled in with the package and either treat the spectacle of it all as a relaxing backdrop, or choose to interact.

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The interaction is limited, to be fair. You can feed and tickle fish, although it's still a fairly passive sport. You do have a good number of configuration options that allow you to alter the mix of fish on your screen (up to 48 at a time can be supported), and tinker with the display and audio options. If you want to, you can easily line up a selection of MP3 tracks to play in the background as well. We had great fun with this: Eminem sounds great coming out of a fish tank!

Yet while Blue Planet 3D Aquarium is a visually striking, strongly animated piece of work, it simply is what it is. Much though the packaging bigs up the artificial intelligence of the fish, much though you may be able to play around with the effect of water currents, it's still just looking at pretend fish on a screen.

That's not to say we didn't enjoy it, but this really is one package that does little more than the name suggests. If you're comfortable paying £10 for an aquatic screensaver, and aren't put off by registration codes, then you're not going to be disappointed by the end product.

The inclusion of a special offer for a family visiting the Cheshire-based Blue Planet aquarium may or may not sweeten the deal for you.

A program with limited ambitions that it easily meets. More so than with most products, you're simply getting what it says on the box.