I will be getting four cherry barbs to add to my ten gallon soon. I already have two in there. I was wondering if it would be okay to add all four at the same time or will this overload the bacteria and the filter and stuff?
it kind of depends. How long has the tank been up and running? I would say since cherry barbs are reasonably small, 4 at once should be okay. Just test your water and watch for spikes. Don't overfeed either! HTH!