Heater causing blindness? o.o

[Foxell]

I recently ordered two new heaters for Sprout and Makoto my newest bettas. I was using a heating pad before as I didn't have any extra heaters on hand. Since I've put their heaters in they're acting as though their blind. They can't see their food, or see me when I go up to the tank or take the tops off to feed. It's really worrying me. Makoto is usually very active and acts all big and tough but lately he's just sitting at the bottom with his fins held together. I can't see how or why these heaters would be causing them to go blind, but it's odd that both of them suddenly can't see after putting them in. Any ideas? I'm really worried about my boys :/

Housing
What size is your tank? Makoto is in a 1.5 gal quarantine tank, and Sprout is in a 5 gal.
What temperature is your tank? 78 degrees
Does your tank have a filter? No
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? No

Food
What type of food do you feed your betta fish? Pellets and frozen bloodworms
How often do you feed your betta fish? Daily

Maintenance
How often do you perform a water change? Makoto, 100% every 3 days. Sprout 100% every week.
What percentage of the water do you change when you perform a water change? 100%
What type of additives do you add to the water when you perform a water change? Water conditioner

Water Parameters:
Have you tested your water? If so, what are the following parameters?

Ammonia:
Nitrite:
Nitrate:
pH:
Hardness:
Alkalinity:

Symptoms and Treatment
How has your betta fish's appearance changed? I believe Makoto's fins may be clamped.
How has your betta fish's behavior changed? Both are acting like they can't see, and they could perfectly fine before. Makoto is also not very active.
When did you start noticing the symptoms? When I put their new heaters in their tanks a couple of days ago
Have you started treating your fish? If so, how?
Does your fish have any history of being ill? No
How old is your fish (approximately)? Sprout is a baby, Makoto not sure but he's new so probably not too old.

[Pataflafla]

Quarantine both from the heaters immediately.

Get them in fresh, treated water and float them in their normal tanks for warmth.

What brands are your heaters and did you rinse them thoroughly prior to use? Also, does your water smell strange at all or have a film at the top? Inspect your heaters for any leaks or cracks, soft plastics and such.

If they don't perk up any after the fresh water, then add 1 tsp/gal epsom salt to see if that helps any (Give them a few hours and change the water 100% before expecting results).

If they get cloudy eyes and still remain inactive and clamped, keep up the epsom salt and water changes (I did twice daily at least after experiencing something similar). I know aquarium salt is recommended for cloudy eyes, but water quality usually causes it, so changing twice daily will help the eyes while epsom helps with anything needing to be leached out of them.

[Foxell]

The heater brand is OceanAqua and on the heaters it says "automatic technic heater'. I bought them off ebay. There's no film on the top, but I just smelled the water and it does have an odd plastic/rubber smell. There doesn't seem to be anything wrong with the heaters, but I'm not going to risk putting them back in ever. I'll be contacting the seller about this.

Neither of them have cloudy eyes. They're currently floating in fresh water. Thanks for your help, I'll keep you updated.

[callistra]

If it's chemical poisoning epsom salts might help. Other than that, looks like you're doing the right thing.

If you're looking for a heater suggestion, a Marineland 25w will work in a 2.5-5g and likewise if you want a little more oomph a 50w will also work very well in a 5g

Just make sure you always rinse anything new in hot water before adding it to the tank. Sometimes I will even soak it a while.

[Foxell]

Well Sprout seems to be doing fine now. I just fed him and he saw the food this time, and gobbled it up. He's much more active as well. Makoto on the other hand is not doing well at all. All he does is sit at the bottom of his tank with his fins clamped. When I wiggled my finger in his water to wake him up to eat he didn't respond at first but when he did he kind of just thrashed around to the top for some air then went back to the bottom. I'm going too add epsom salt just in case. I'm really worried I'm gonna lose him :/

[MissFutureVet]

I had the same problem. I think my heater is leaking to. I did a regular weekly 100% water change and 2 days later , there was a layer of film on the top, my betta just laying around, and he is normally really active. He still acted normal when I walked to his tank and ate his as usual. But last night i noticed the film had started to not only be on the top but throughout the water as well. I immediately did another 100% change. I will keep an eye on his tank to see if it gets cloudy again too soon.

[Pataflafla]

Have you changed any water in Makoto's tank? If you still have the betta cup he was in, I strongly suggest using that for quarantine with freshwater and twice daily water changes along with epsom salt.

[Foxell]

Yes I completely changed his tank and rinsed it out really well, gave him fresh water then added the epsom salt. Bad news though, he passed away this morning :/ I was really hoping he was going to pull through but now I'm wondering if maybe there was some underlying problem with him, because Sprout is fine. Ughhh D:

[Sena Hansler]

Some bettas can survive so many things...other may not be able to... he could have been internally weaker than your surviving boy. The rubber/plastic smell, tells me there was something leaking into your tank from the heaters - I've had that only once, and I threw awya the heater.

If you ever get new heaters, test them before putting them in - usually a water bucket works, or an unused tank, approximately the same size as what you have... Then you can find out if it overheats, doesn't heat, froths, smells, etc.