Mega Pirahna is awesome, and you can get it on a DVD two pack with Mega Shark vs Giant Octopus which is even more awesome.

The comparison between the Sharktopus and Dinoshark is easily drawn from them both being a part of the big & silly aquatic monster movie glut of late.

The only reason I kinda thought Dinoshark was an interesting diversion from the rest of the school, though in itself not interesting enough to purchase, was that the acting was at least decent, the script had plausible dialogue, and the makers didn't go overboard with the monster attacks... like making it climb onto land to eat people... which actually would be fun to watch.... but not when you marry real people with bad video game level CGI. Maybe when the technology, or investment in better, existing CGI is used for these films, I'll laugh at such monster attack concoctions; but for the right reasons.

Of course... the film faltered in the narrative / plot department. The script waited far, far too long to tie in the main cast with Dinoshark killing stuff. Both narratives seemed to run on two separate story lines, and when their tracks finally crossed, it was too late and the movie had become tiresome.

My favorite giant sea monster direct-to-DVD pic of the post millennium is still OCTOPUS.