I'm not big into keeping fish but i do have one fish in a 5 gallon tank. The tanks inhabitant is a platinum gourami. I recently added a chinese algae eater to the tank but he bothered the plat gourami so much i had to remove him. I've had the plat gourami for almost 2 years now. Due the fact that i added the CAE, I was reading up on gouramis and saw that they could get larger than my current one which is about 2 inches, do you think he will get much bigger and need a larger tank or is this 5 gallon tank and one fish fine till i decide to stop keeping fish?

I'm not sure how big a 5 gallon tank looks, but as long as its only 1 gourami, it should be fine. Strange though that your gourami is only 2 inches after 2 years. My gold gouramis, which is the same as a platinum, just different colours, grew to full size of 5 inches in about 8 months or so.

Actually 2 inches sounds very tiny, are you sure about your measurements?