I don't know about with self-watering pots but I use conventional pots and water with Optimara AV fertilizer every time. The plants do great with it. The key is having very dilute fertilizer, and the Optimara has directions on it specifically for watering AVs.

Lisa-

you are giving your plant already naturally fertilized water - fish emulsion of a sort - and as long as it works for you - I wouldn't change it. If you want to try Optimara fertilizer - and it is a very good one - you can every so often - let's say every 4th time - refill your pots with 1/4 teaspoon per gallon solution to add some trace elements and what else that can be lacking. You will see if your violets will benefit from it or not and decide if you want to do it.

Irina