I also agree with them just being skittish because of their nature. I have 3 Balas as well, they are in my 450g. pond and are about 9 inches. I've had them for 2 years and when i got them they were about 4 inches, so they've grown roughly 4-5 inches in 2 years, being fed on omega one and bloodworms, so this gives you an idea how slowly they grow, its not like you have to run out to get a bigger tank within 1 month. If yours are 3" max. right now, they're just babies still. Its not like you need a huge tank right away! I think some people are going to far with this, i mean, yes, he/she (mikel) bought a 29g. tank, maybe didn't do enough research on the balas and brought them home. Now they're acting skittish for whatever reason and trying to figure out why. Atleast he/she is trying to do the best they can with what they've got to work with, regardless of the fact that the balas will EVENTUALLY out grow the tank. It could be worse, it can always be worse. So, to end this off, they may just be acting skittish because they are quite a skittish fish. Also, since you were gone for a week or however long, they may became accustomed to the food coming into the water but no one around the tank. Then, all of a sudden you come home and they're not used to that. It might take them a while. I have never left my balas (or any fish) with an automatic feed when i leave. They can go without eating for a week or more.