Blue Acaras Rescued

What would be a good tank size to keep 5 blue acaras? As they are still small (2-3 inches long) they are in my 29 gallon but they will soon outgrow this tank. I wanted to stock this tank with some smaller species of cichlids, but when I saw these 5 blue acaras in a dirty 5 gallon, with damaged fins, I couldn't resist and took em home in my 29 to try to save them. After only 4 days of treatment they feel much better. I used melafix / pimafix along with some salt in the water. At first they had some sort of white cloudy mucus on their body, making them hard to use their pectoral fins, they were scraping on rocks, etc. 4 days and the white mucus is gone, they swim with ease and they have a good appetite so I guess I'm on the right way. I will try to acquire a bigger tank to keep them, or at least I will keep a couple and try to find a nice place for the others but I'm wondering on the size of the tank to get for them. I've read that a 55 gallon would be OK, I need some advice, thanks.

Here are some pics, sorry for the poor quality I only have my Palm to take pics