discus help than you

Question
Hi there, i am Dan and i have a few questions. I recently bought a neon blue discus which is in a 40 gallon tank with a firemouth, pleco, tetras, tiger barbs, and a puffer. Everyone gets along great. There is no aggression and they seem perfectly healthy. However, my discus is not eating. I just got him 2 days ago and he is not eating. I tried feeding him bloodworms, flakes, and pellets, none which he seemed interested in. What could be wrong? He seems healthy and doesnt have any signs of illnesses except for not eating. The tank is fully cycled and i do 50 percent water changes weekly. Do discuses   NEED other discuses or will
they be fine alone? I really only wanted one because i dont have much room and discus are really expensive! How many discuses can fit in a 40 gallon tank? So what do you think the problem may be? None of the fishes seem to be bullying him and nitrite, nitrate, and ammonia are all fine. Is he just getting settled in? If so, how long will it take for him to fully get used to the tank and start eating? Please help.I have a few more questions. Will my discus starve? Will he know he needs to eat? Or will he go on a hunger strike and not eat? Also, how do i make my water softer, and can you give me some species of cichlids that need hard water so i wont keep them together? Last, is there a way to test the ph without keep on buying test strips? Thank you. And sorry for the lenghy question.

Answer
Hi Dan:

It is a little bit normal for your discus to not be eating yet.  He is probably a little stressed out from going from the aquarium to your tank.  Also if the Discus is new to the aquarium he may still be trying to overcome his journey from the fish factory to the aquarium...some of these exotic fish come all the way from Asia and during transport they are not fed...so they get use to not eating during that time and that behavior sometimes carries over to the hobbies aquarium.  In general for everyone who reads this do not hesitate to ask an aquarium to feed any of the fish you want to purchase... you should make sure that your fish will eat.  If you find difficulty from that aquarium... find one that will accommodate you.  Sometimes when you have a wide variety of fish in your tank you may need to buy specific types of food for each fish... some fish prefer fish food that sinks, other prefer food that floats, and yet some prefer to chase their food through the current in the tank.  As for how many discus you should put in your tank... I would first say... it depends on the size of your discus and your tank.  For 40 gallon tanks that are your basic rectangle...I would say 4-6 discus and very little else.  I am concerned about your puffer...or rather the other fish in your tank... Puffers are one of the most aggressive fish I have ever encountered.  Save yourself some grief and separate that fish from the rest...especially if you are going to keep discus...because you will wake up on morning and find large parts of the discus fins missing.  to sum it all up... your discus should start eating soon...if it doesn't start to eat, change the food you are offering and/or return it to the aquarium and exchange it for one that will eat...and separate that puffer... dave