Hi Gavin,
Firstly freezedried anything really isn't nutrionally very sound so you might like to feed other food varieties.
For staples i recommend live earthworms, blackworms, bloodworms and pellets. For occasional treats i recommend bits of fish, shrimp, beef heart strips (although i like the word julienne). And good news they all sink!
Here are some links i think would be useful for you to have a better understanding of nutrition for axies.
http://www.caudata.org/cc/articles/foods.shtml
http://www.caudata.org/cc/articles/foods2.shtml
http://www.caudata.org/cc/articles/worms.shtml
http://www.caudata.org/cc/articles/microfoods.shtml
Live food are really nutrionally very complete and have the added bonus of stimulating the axie's appetite by their wriggly movements. The axie has special vibration sensing receptors which makes them think MEAL TIME!
You can do as the rest suggested and try hand feeding them or use feeding forceps or you can drop in some live earthworms in front of their faces and let them hunt. They are opportunistic feeders so its really quite fun seeing them root around for food.
If you use a feeding bowl and if you feed at a regular time (routine), you can actually somewhat 'train' your axie. Whenever its meal time, my axies come out from the hiding spots and await in anticipation near the front of the tank or see me walk by.
Also axies are crepuscular (Eva's favourite word), and are most active at dawn and the evening, so feeding them around these times would be ideal.
Last but not least, if you are willing to quarantine feeder fish or freshwater shrimps for a period of 30 days minimum, you can actually put some in your axie's tank as feeder fish/shrimp. They are occasional treats that the axie can work for by hunting.
Cheers.