Hi,

are you sure about the 0 NO3? That is highly unlikely (impossible in a cycled tank). Your other readings are fine, but I would check the test kit to make sure that it works correctly.

100% changes disturb the natural bacteria fauna a great deal and shouldn´t be done on a regular basis; just stick with your weekly 25-50% changes.

The food you use is fine as long as it isn´t freeze dried; wet frozen or life would be ok.

From what you describe, the "seizures" seem to be simple startle responses (although I can be wrong here without seeing it myself). The forearm movements match the normal ACF foraging behaviour as far as I can imagine from your message. However, an ACF wouldn´t stop eating for no reason. The frequent shedding also shows that something might be out of order; are you sure that he doesn´t show any other symptoms? Sorry, I´m at a loss here But earthworms are worth a try, I don´t know of any ACF that doesn´t love them. The ones you can buy are fine.