[xxshabsxx]

So I've got a 450L tank. I've not changed anything with the tank in months. The things I'm dosing the tank with, the filters, how often I water change, what I put into the tank after I water change, the light period, the food etc... Literally NOTHING has changed.

2 days ago, I turned my room lights off to sleep (my tank lights were already off). The fish went balistic! I turned my room lights back on, and they were fine. I had to get to sleep, and can't sleep with no lights. Turned my lights back off, they were balistic again, then quiet. They're NEVER done this before. Wake up the next morning. 3 of my good bosmani's are dead. Fish I've had for literally years, and just dead. No signs of any disease, anything.

So I did what anyone would do, and did a water change in the case that there was something in the water. A BIG water change (>30%). Turn the lights off that night and the fish went crazy again. It seemed to be just one fish, and old Rainbow I've had for 7 or so years. Next morning, another Bosmani is dead.

I called the local aquarium, and spoke to the expert (the owner), who said it must be the Rainbow that is going crazy (when I called, the Rainbow was running into the glass, other fish, plants, the graven and getting stuck under driftwood. So I did what I had to do, and disposed of the fish (as he would have killed himself sooner or later). I took the day off UNI and watched the fish really carefully. I mean, really carefully. They were all fine, nothing crazy. One thing I did notice, was their on their top lip (if you call it a lip) was white, possibly damanged.

Anyhow, about 5 minutes ago, the lights turned off (I've got it on a timer), then all of a sudden one Bosmani went CRAZY! One that was fine before, just went absolutely mental. Running into everything. He is now swimming at the top of the tank, sometimes swimming upside down.

WHAT DO I DO? I've so far (easily) lost over $200 worth of Bosmani. This is killing me. I've tested the water, and everything is fine. Nothing over the oridinary.

 

[fish jihad]

My fish go a little nuts when i turn the lights off at night and again when I turn them on during the day. Nipping each other, alot of chasing each other around the tank for a minute. But this sounds more severe. If they are old fish, perhaps they are just going blind. The sudden switch to darkness may cause panic is a fish with failing eye sight.
But the fact you have a Bosmani who was fine before but now is going nuts left me perplexed. So try using a dimmer (only on LEDs i think), so the transition to dark is more gentle?

Thats all I got. Unless you have some sort of bizzare electrical short that zaps the tank when you turn the lights off. Im an electrician, so there is really no chance of that unless something has gone horribly wrong.

 

[xxshabsxx]

My fish go a little nuts when i turn the lights off at night and again when I turn them on during the day. Nipping each other, alot of chasing each other around the tank for a minute. But this sounds more severe. If they are old fish, perhaps they are just going blind. The sudden switch to darkness may cause panic is a fish with failing eye sight.
But the fact you have a Bosmani who was fine before but now is going nuts left me perplexed. So try using a dimmer (only on LEDs i think), so the transition to dark is more gentle?

Thats all I got. Unless you have some sort of bizzare electrical short that zaps the tank when you turn the lights off. Im an electrician, so there is really no chance of that unless something has gone horribly wrong.

For fear that I'll lose anymore, all of my 'precious' ranbow fish have been relocated to a neighbors tank (well one of his 70 or so tanks). He was the one who sold me the fish years ago, and never heard of anything like it. Upon inspection, he noticed that the mouths of the fish looks a little white, to which he immediately noticed was due to the fish running into the glass, most likely due to the stress of the lights suddenly turn off. He is, though, completely unsure to what is going on.

He has been working (and breeding) australian natives for the past 20 or so years. And has never seen fish (that were in the tank as long as mine) all of a sudden go ape and dislike the changing of the lights.

Anyhow, we shall see what happens in his tank.

 

[caique]

Sorry to hear about your loss, loosing precious fish is no fun.

 

[King of Hyrule]

I'm guessing the water test results were normal?

Are the fish freaking out in your friends tank?