Betta Rescue Gone Awry, Please Help!

So, I've had a bit of bad luck with my betta aquarium lately. First, my old betta who was over 6 years old passed, that was expected, the poor guy had hung on forever.
A few days ago I got a new betta for my old setup, with the thought that I will soon do an upgrade to a nice built in filter planted 5 gallon. Currently it's a sparse 5 gallon, but still 5 gallons with at least weekly water changes. This new betta I had gotten seemed to really enjoy the java ferns I had gotten for my previous betta, an easy plant that a LFS told me would be great for betta fish.
Well I went out to get about half the gear needed for the upcoming planted upgrade and I find my new betta dead. I really liked this guy so obviously I was upset. I tested my water chemistry, the temperature, everything seemed fine. Then I thought it was odd that his body had been under the java ferns so I do a little digging. Sadly I did not know that bettas could get trapped under java ferns ribosomes and root systems and suffocate. Still, since the LFS had led me astray I was going to cash in on their 30 day live fish guarantee, unfortunately that meant I had to go with a new betta now, or lose out on money. Which brings me to my current problem.

Considering the fact that I had to get a betta or lose out on that money, I decided I'd do a rescue since the aquarium is mostly bare now (the first thing I did was rip those awful java ferns out of the aquarium) and should be a good place for a betta to recoup and come back into health while I finished gathering things for the upgraded planted aquarium.
So I get home with this new new betta, do a quick water change, test everything, then I float the cup to temperature acclimate him. Here comes the problem:
I check on the new new betta about 10 minutes after I started floating the cup and I assume it drifted too close to the filter output or something, because the cup had sunk and the betta was stuck up against the filter intake. I thought he was dead since he was already one of the betta not doing so well in the store. I coaxed him off and now he's laying on the bottom, still breathing, but obviously not doing well from the shock. The light is off right now, the filter is on the lowest setting it can be, but I'm still not sure if this guy is going to make it. Is there anything else I can do to bolster his chances to pull through?

 

You should make sure you have an intake cover next time to prevent anything similar from happening again. Indian almond leaves or Stressguard which have therapeutic and antiseptic properties can be added to promote the healing process.

 

Your java ferns did not kill your betta. Java ferns and bettas are a perfectly safe combination. My betta loves the java fern in his tank and spends a lot of time around it.

It sounds to me like your filter is the actual problem. Filters can and do harm bettas if the flow is stronger than they can handle. You say you have newly upgraded, it sounds like the flow was enough to kill the previous betta and has already harmed your new one. Personally I would not use a filter with such a strong flow, even with an intake cover. Sponge filters, which are extremely inexpensive, are a great choice in a tank with a betta.

You also should know that with a new filter (preferably not the one you're using now), you will need to cycle the tank/filter before it's really safe to add a betta. Your profile says you know about the nitrogen cycle. It's really best for a betta to do a fishless cycle (which will take a month or so) before you add fish.

 

No, I got the stuff for the new aquarium. This is the old one still, I haven't switched anything. There is no cycle happening. If I were to start a new filter I would move over the established ceramic media.
The filter did not kill the last one, he was swimming just fine. There were absolutely no indication that he was ill or struggling. He swam strongly and loved exploring.

I'm going out to get some stressguard now.

 

Personally, if I had plans on getting a new tank, I would've held off on getting a new fish. There's no point in putting a new fish in a new environment and then later doing it again.

Java ferns are safe for bettas. You weren't "led astray." Accidents happen unfortunately. Bettas are usually curious and sometimes fish try to explore where they shouldn't. Just make sure there's no places in the tank that he could get stuck in; that's all you can do.

You definitely need to get an intake sponge for the filter.

I hope your betta pulls through.