Help! Fish dying and I don’t know why!

[EDKexotics2003]

Have you tested your water?

Yes

If yes, what is your ammonia?

0ppm

If yes, what is your nitrite?

0ppm

If yes, what is your nitrate?

0ppm

If I did not test my water...

...I recognize that I will likely be asked to do a test, and that water tests are critical for solving freshwater health problems.

Do you do water changes?

Yes

What percentage of water do you change?

41-50%

How frequently do you change your water?

Every two weeks

If I do not change my water...

...I recognize that I will likely be recommended to do a water change, and water changes are critical for preventing future freshwater health problems.

I’ve been keeping fish for a while and have kept pretty much everything under the sun yet I have no clue what’s going on in my 75 gallon biotope. About 2 weeks ago I lost three juvenile red head tapajos each 2 days apart from eachother, all eating well, fully colored up, healthy looking fish. After they died I figured it was a fluke, I tested everything under the sun in terms of conditions and everything is perfect. Next my svenis started to go, each 2days apart. They would be stunning and completely fine, I would turn the lights off then they’d become boisterous and wild, ramming into walls, wood, rock, until they’re stunned, after 20 mins of this behavior they drop dead, this happened with the tapajos, and now my svenis, there is no one bullying them, and they would only look stressed minutes before they died. No external signs of illness, fully colored up. Worried my other fish are next please help! Photos were taken an hour apart!

 

[neko1]

is that white spot next to the pectoral fin normal? I dont think i have ever seen it on a geogphagus. kinda looks like fungi or an internal bacteria

 

[EDKexotics2003]

is that white spot next to the pectoral fin normal? I dont think i have ever seen it on a geogphagus. kinda looks like fungi or an internal bacteria

It’s a glare from the camera light I freaked out a bit until i watched the Live Photo.

 

[esoxlucius]

I'll address the obvious glaring issue first. If this tank is established you should have a positive nitrate reading, not 0ppm.

Initial parameter readings of 0,0,0 usually indicate something is amiss. Can you elaborate on this?

 

[EDKexotics2003]

I'll address the obvious glaring issue first. If this tank is established you should have a positive nitrate reading, not 0ppm.

Initial parameter readings of 0,0,0 usually indicate something is amiss. Can you elaborate on this?

This tank is also a grow out for some ray pups, the rays are especially sensitive to nitrate levels and can become dangerous when exceeding 10ppm. The tank just got a water change so levels are at 0 I don’t expect them to stay that way but I try and keep them as low as possible. The tank has been set up and running for the last year there is no way that it is not cycled. Also doesn’t explain the individual species of fish dying one by one. If it was a water issue I believe my most sensitive fish would have died first instead of my captive bred red heads and almost full grown svenis. I posted this on multiple other threads a lot of people are saying they think it’s a protozoan parasite but not too sure yet.

 

[phreeflow]

That’s very odd. Sorry to hear about the losses. I had this happen to me once before but it was when I did a water change and forgot to add dechlorinator. Not everything died but about a third did in the same manner as yours. They’d panic and go nuts banging about and would drop dead.

I’ve also known a person who miscalculated and added way too much Seachem Safe and also lost fish the same way.

Also, have you checked to see if you have any stray voltage?

 

[EDKexotics2003]

It is! I was worried about stray electricity so I took out my heater, and power head, (the only two wires touching the water) since then I’ve lost two more sveni so I don’t think it could be that. As for the declorinator it is possible I added too much Prime but I still would’ve figured if that was the case the ray pups, more sensitive geos, and some of the other more sensitive fish would’ve died as well.

 

[Denon]

Have you added anything to your tank recently? New rock, new wood etc?

 

[Deadeye]

How is the surface agitation? Do the fish ever act off before dying? Low oxygen/high CO2 could be an issue - I’ve had a tank wipe out from it. The fish are fine at first, but quickly go listless until dying.
Try attaching a video.

 

[fishdance]

Sorry to hear your troubles. Erratic swimming, dark colour, fast deaths usually indicate chemical toxicity.

Fly sprays? Pest treatments? Unwashed hands in tank? Change in supply water?

If your unsure what's happening the golden rule is a large water change which you have alreaady done.