Frozen Foods

I have tried several different types of frozen food - bloodworms, daphnia, chopped mussel, mixed. As a general rule the fish love them. I think it's a great idea to try something different in the diet, to increase the variety and add interest. Not all fish will love everything, but I think it's always worth giving it a go.
As for cutting them, I have found that putting a chopping board down, then covering it with something like paper towel (so the cube doesn't slip), then put a sharp knife (I use one of the kitchen knives) resting on the cube where you want to cut it, then hit the knife directly above the cube. If that doesn't work for you, then you can always try to shave slivers off the cube from one end using the knife in a similar manner, but it avoids having to hit the knife.
Have a play around with techniques and you'll find one that works for you. defrost the bit you need, pop the rest back in the freezer.
Your fish will probably go nuts for something a bit different. 

I tend to use live food these days because the dwarf puffers are a bit fussy about food that doesn't move.
I use the bloodworms as the main diet for the puffers and the mudskippers.
A tube costs £1, and kept in the fridge can easily last a week (except not with my gang).

I use frozen 'live' food as well.

One thing about freeze dried is that it has been known to rehydrate and swell up inside the fish, which doesn't do the fish much good. It is better to soak freeze dried 'live' food in a bit of tank water before putting it in the tank.
The same applies to some commercial pellet food. It is always recommended to soak betta pellets, for example. Except my current betta won't eat soggy pellets.....

My husband doesn't like frozen 'live' food in our freezer either. To placate him, it is wrapped in 2 freezer bags.
@adenann would your wife allow it if you kept it sealed in a plastic freezer box?

I got some of the freeze dried stuff, should I mash it up a little as seems quite large for some of the fish?