Neon Tetras slowly dying off

[Denther]

Hello all. I haven't been around for a while since I haven't been having any issues but now I do have one. My neon tetras are dying.

About 3 weeks ago 1 of them started developing bulging eyes and swimming around in a very twitchy fashion. It would avoid the rest of the group, and as the problem progressed, would swim against the bottom corners of the tank as if trying to escape. He died then a week later another one died. Today the third has passed and a 4th is beginning to exhibit problems. My cory cats seem fine.

Thoughts?

 

[lauraf]

First things first...what are your water parameters?

 

[OrangeCones]

Also could you post a pic of the fish alive but starting to suffer from the same issues as those now dead?

 

[Denther]

I actually don't have any test kits. I never have. I probably should get those. Any good cheap ones?

I'll see if I can get a picture but I'm away from my tank until Sunday. Hopefully he's still alive then. This one I've noticed. Seems to swim at a 45 degree angle. His head higher than the rest of his body. Appetite in all the fish has been fine.

 

[Fuzz16]

How often do you do water changes?
How long has tank been setup?

 

[Denther]

Tank has been setup for almost a year. I've had no problems except for a few algae blooms.

I change my water every week to week and a half. About a 40% change.

 

[skjl47]

Hello; Any idea how old the neons may be. Small fish do not always live a long time. Could it be they are simply getting old?