Nutrafin Basix Freeze-Dried Blood Worm. Freeze-dried foods offer higher protein values than many other fish foods. They contain very little moisture and have a very high nutritional value. Nutrafin basix Blood Worms are a completely natural freeze-dried organism that will be devoured by finicky or newly imported fish. Nutrafin basix Blood Worms provide a supplementary diet for all tropical fish. This highly nutritious food should be incorporated into the feeding regimen of most tropical fish. Bottom feeders should be feed with Nutrafin basix Staple Food Tablets. Available Sizes: 9 g (0.3 oz) / 19 g (0.7 oz)