I hope someone may have some idea of what is going on in my tank. I have a 125 gallon that has been set up for over a year and a half. Rainbowfish, cherry barbs, Congo tetras were all doing fine yesterday. When I fed today, the tank looked a little empty. I noticed 3 female Congos were missing and one turquoise rainbowfish was dead. About an hour later, one male Congo was dead and 2 other rainbowfish were sitting still in the upper third of the tank. Checked a couple hours later and one of the rainbowfish, a cherry barb and one of my Bristlenose plecos were all dead. What could be going on??? Ammonia 0, nitrites 0, nitrates between 20 and 40. Water looks clear. Very small amount of black algae on a few big rocks that is kept under control by nerite snails and BN plecos. Temp 75.4° 50% water change done about 10 days ago. Aquaclear 110 HOB filter and 2 large sponge filters. Prior to this, last fish death was quite awhile ago.
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8 fish dead in less than one day
- Thread starter pednurkim
- Start date
Nitrates are a touch high, but not high enough to cause a mass death in only a few hours.
Did you introduce anything new to the tank? Disturb any of the substrate? Move decor around?
How are the fish alive behaving? How did the ones dying behave?
Did you introduce anything new to the tank? Disturb any of the substrate? Move decor around?
How are the fish alive behaving? How did the ones dying behave?
Nothing new or moved in the tank. Substrate a little less disturbed since my 2 corys died. The Kribensis attacked them. One rainbowfish is swimming a little tilted on end, but has been this way for a couple months and is eating well and good color. One other rainbowfish has some dark areas on it, but is still swimming around and eating. The ones that died looked perfect. The rest seem fine.
Can you post photos of the 2 rainbow fish you mentioned?
Has anything been sprayed near the tank? Or could a toxin have gotten into the water on your hands, from a bucket etc.? Do you use dechlorinator? Do you use cold water for water changes?
A water change any time a fish dies is advisable. Dechlorinate and temperature match the new water.
Has anything been sprayed near the tank? Or could a toxin have gotten into the water on your hands, from a bucket etc.? Do you use dechlorinator? Do you use cold water for water changes?
A water change any time a fish dies is advisable. Dechlorinate and temperature match the new water.
Did you have visitors yesterday?
What did you do to the aquarium yesterday?
Did you have anything on your hands (cream, oil, grease, hand sanitiser, etc)?
Need pictures of the dead and live fish.
Do a 75% water change and gravel clean the substrate immediately to dilute whatever poison is in the tank. Do another 75% water change and gravel clean every day for the next week to remove whatever is in the water.
Make sure any new water is free of chlorine/ chloramine before it's added to the aquarium.
Increase aeration/ surface turbulence.
Make sure nobody has put anything in the tank or used buckets or anything fish related for another purpose.
If the rainbowfish have black patches and they weren't there yesterday, it is poisoning from chemicals in the water. If the fish survive, the black patches go after about a month.
What did you do to the aquarium yesterday?
Did you have anything on your hands (cream, oil, grease, hand sanitiser, etc)?
Need pictures of the dead and live fish.
Do a 75% water change and gravel clean the substrate immediately to dilute whatever poison is in the tank. Do another 75% water change and gravel clean every day for the next week to remove whatever is in the water.
Make sure any new water is free of chlorine/ chloramine before it's added to the aquarium.
Increase aeration/ surface turbulence.
Make sure nobody has put anything in the tank or used buckets or anything fish related for another purpose.
If the rainbowfish have black patches and they weren't there yesterday, it is poisoning from chemicals in the water. If the fish survive, the black patches go after about a month.
If water parameters and toxins are ruled out, you might have an aggressive fish issue.
With Kribensis cichlids, you might encounter territorial disputes around caves. They are highly protective of the area. This behavior is even more noticeable in times of spawning.
Kribensis cichlids should not be kept with other cave-dwelling species.
With Kribensis cichlids, you might encounter territorial disputes around caves. They are highly protective of the area. This behavior is even more noticeable in times of spawning.
Kribensis cichlids should not be kept with other cave-dwelling species.
GailH
New Member
Colin_T may be onto something there. Especially if you had visitors who had kids with them. An unsupervised child (here, sweetheart, watch the fishies) can introduce any number of things into a tank, either thinking they are "helping" or, as I've know to happen to others, because they are just mean spirited and/or jealous kids. With such a sudden change and die off, I too am inclined to believe there is a poisonous substance at work here.
Usually every week to 2 weeks
Nothing sprayed near tank. I always use Prime and matching temperature water with water changes. Heaters are working. This morning more are looking quiet. These have less color and some clamped dorsal fins. The rainbow with the black stripes is the one that has been swimming slightly tilted for a couple months.
Attachments
No one different here. I didn't do anything with the tank, so no hands in it. Today, one of the fish is kind of annoying the ones that aren't swimming as much, but none of the fish act aggressively normally. Doing big water change now. I have sand, so have never done deep sand cleaning. Adding extra air stones.
My Krib has only been aggressive to the 2 corys I had. He leaves everything else alone. He also mostly stays at the bottom and most of my fish losses stay in the middle and top.
My cat sometimes gets on the tank (tried everything to keep her off). Maybe she could have gotten something into the tank??
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