Sick Betta Or Lazy Betta? Please Help

I brought this guy home from PetSmart a couple of weeks ago and his activity levels are up and down. Sometimes he just chills at the bottom of the tank, tucked into the corner, or hiding out in the little arch in the décor. I've worried about it before because he just seems pretty listless in his tank but then other times he's fairly active in swimming around.
 
I did notice that when I put food in the tank for him, I don't ever see him eat.
 
Tonight I went in to turn off his light for bed and he was at the bottom of the tank, laying on his side and it looked like he was gasping.
 
There doesn't appear to be anything wrong with him, so I have no idea what could be wrong. Please help. He's so beautiful and I don't want to lose him.
 
I have a test kit but my roommate just put melafix and some aquarium salt in there so I don't know how that might skew the test results.

GET THAT MELAFIX OUT!!!

Anything that ends in fix contains a type of oil that coats the labarinth organ, preventing it from being able to breath.

Do a 90% water change ASAP with dechlorinated and temperature matched water. Then, in about an hour or so, do a 50% water change.

Before you do the water change, take a sample of water, then, after the water change, test it to find out the readings of the tank, them post the exact results on here.

Along with that, did you cycle the tank? If so, how did you go about doing this? What is the temperature?

Blondielovesfish said:

GET THAT MELAFIX OUT!!!

Anything that ends in fix contains a type of oil that coats the labarinth organ, preventing it from being able to breath.

Do a 90% water change ASAP with dechlorinated and temperature matched water. Then, in about an hour or so, do a 50% water change.

Before you do the water change, take a sample of water, then, after the water change, test it to find out the readings of the tank, them post the exact results on here.

Click to expand...

This.  Also, use carbon to get the rest out.  I have heard that bettas don't like salt either.  It's generally a bad thing to just throw medication and treatment without pinpointing a reason that warrants it.

Well, luckily I haven't killed him yet with my lack of knowledge.
 
I did a 90% water change for him this morning. I was swimming around pretty frantically in his tank in between periods of laying on the bottom. He'll like, zoom around in his tank with no rhyme or reason, and then he'll go to the bottom of the tank and lay there.
 
He went into a new tank set up, so it was not cycled before I put him in there. Before I put him in the new tank I just had him in a fish bowl for a couple of days with no filter and no heater until I could get his tank. He has a heater in his tank but I don't know the exact temperature because I don't have a thermometer for him, the set up didn't even come with one of those little stick on ones.
 
I didn't know about bettas and melafix. She (my roommate) just squirted it in there last night and I asked her if that was too much because it looked like she put a lot in compared to the size of the tank so she said it would be fine and since she has a little more experience than I do with aquarium keeping I thought it would be okay. Now I know better. No melafix.
 
I feel really stupid and I hope it doesn't cost my lil guy his life.
 
I did the test on his water and here's what I've got;
 
pH: 7.6
Ammonia: 5.0 (ridiculously high, it was the most green I've ever seen on a test)
Nitrate: 2.0
Nirite: 0.25

Just did the second water change of 50%. I hope he'll be okay.

Are you using liquid or strip tests? And when can you pick up a thermometer? You need one to be able to see what temp the water is as he needs to be kept at 78-82.
Have you read the Betta Care article at the top of the page?

THIS article.
 
What test kit are you using?
 
Do you have any other tanks running? Or know anyone that does? If you do, you can take some of their filter media and put it in your own filter, this will help with your cycle, and will hopefully help in the ammonia levels.
 
Another reason why your boy was showing those signs, is because he was probably suffering from ammonia poisoning, since the levels are so high.
 
Whenever you see those signs, it will be best to do a water change.

He didn't make it. I came home from the store and he was on his side not moving. I nudged him and he didn't even flick a fin. I left the room to get a net and when I came back, he was belly up.
 
I've read that article on betta care.
 
I just didn't get my test kit in until a day ago (it's a liquid test kit) and by then he was already showing signs of lethargy. He hadn't been very active even since I brought him home from the pet store.

Also, I bought a thermometer for his tank today, the water is at 78 degrees. I'm thinking about moving Brutus, my other betta, out of the community tank because he chases the other fish around, and putting him into the 3 gallon I had for Raphael.

Sorry for your loss! 
Moving Brutus might be a good idea.

I'm sorry to hear that he didn't make it

Hello! The same thing happend to me, but i didnt use metafor or what it was called. I was thinking it was the temprature beacuse a lady (i didnt brought it from the pet store She was in) in a pet store said that my betta should Stay in 15-20°c so i did, but my betta was just laying lazy and i thought he was dying. I didnt change the water temprature til 27°c untill now and when i did now it worked perfectly, He is in full speed! Maybe the temprature is wrong, he is born lazy (mine is active and lazy) or it night be too small or too much in his aquarium. I hope this helped!

Bettasisawesome123 said:

Hello! The same thing happend to me, but i didnt use metafor or what it was called. I was thinking it was the temprature beacuse a lady (i didnt brought it from the pet store She was in) in a pet store said that my betta should Stay in 15-20°c so i did, but my betta was just laying lazy and i thought he was dying. I didnt change the water temprature til 27°c untill now and when i did now it worked perfectly, He is in full speed! Maybe the temprature is wrong, he is born lazy (mine is active and lazy) or it night be too small or too much in his aquarium. I hope this helped!

Click to expand...

In this case, it was the very high level of ammonia that killed the fish, nothing to do with temperature.

Unless you cycled your tank before you got your betta, it was almost certainly ammonia poisoning that made your fish sick as well, although the low temperature would not have been good for your fish either.