Waynemagic64

After 4-6 days I woke up and 2 of the 3 were dead and the other was at the top like it was gasping at the top of the surface. Tested the water and the parameters looked good again. Only thing I could come up with is that they were oxygen deprived somehow. I added a sponge filter, changed about 50% of the water to try and save the last fish but with no avail. Starting to get a little frustrated here. Any tips? The built in filter should have been fine for circulating the water for oxygen right? I'm running out of ideas to keep these fish alive. Should I clean out the tank completely and start over?

I bought an ammonia test kit and it wasn't high at all. It tested yellow the lowest level. I got my fish from my local petco. I live in MN and they said I should set my heater to 72-76. My water tested fine all the way around. Now I just got 3 lil zebra danios in the tank now. We'll see if I can keep these alive.

I used the 7 in 1 test strips and GH, NO2, NO3, CL2, KH and PH are tested. The only one that's close to outside of parameters is the PH at like 7.5. The GH is close to the 0 area as well. We've had the tank for like a month with artificial plants. I believe the tank is cycled not exactly sure. I have done partial water changes to clean up debris. I did try 4 neon tetras in the tank with this latest betta cuz I saw they were good tank mates for bettas on some online videos. The kids enjoyed them but I'm pretty sure the betta killed them overnight...

I've had a gold fish for a few years for my son when he started going to school. My daughter is now 4 and we decided to get her a betta tank. We got a Aqueon LED MiniBow 5 Gallon tank and got a betta. Fish we got a water heater and keep the temp around 78-80 degrees. We have artificial plant and the longest we've been able to keep a betta alive in the tank is 2 weeks. I've used test strips and the only area that I'm close to being out of ideal ranges is PH around 7.5. Does this filter have too much flow? Just wondering on some tips to help me out.