It sounds like you have a nice mix of fish

For the long term, yes your tank is to small. I would say that you'll probably be fine with a 55 gallon tank for a few more months, but you'll need to upgrade soon. For the time being, keep an eye on your
nitrate levels and do extra water changes if necessary to keep them from getting to high. I would check craigslist for great deals on big tanks. Right now with the economy the way it is, it seems like people are selling tanks for cheap left and right. I would love to see pics of your fish and tank as well
