Can fish just... die?

Howdy,

move had my tank up and running for a few months now. I fishless cycled it and it has a school of cardinals and rummynose, a shoal of kuhlis, a lemon bristlenose pleco, and a pair of rams.The rummynose have been in the tank for about a month, maybe month and a half now. All we’re doing fine, and then I woke up this morning to one dead. Ammonia and nitrites are 0 ppm, and nitrates are <10 ppm. They were all active and eating yesterday morning, and this morning all of the other fish looked fine, as well. Can fish just randomly die, or is there always an underlying cause? The last time I did a water change was a week ago, and I was supposed to do another one today. What should I do? No other fish seems to be sick.

 

I know that fish tend to die duringnthe first few weeks in the tank but he was there for a while. So I don’t know what it was.

 

It is possible.
You time frame would also coincide with new tank not cycled syndrome, or even to many fish added to an existing cycle that couldn't' keep up.
There are other factors like disease or fright from something weird.
Keep an eye on things and keep it clean.

 

I would continue with your normal schedule. Sometimes fish just die for seemingly no reason, I’ve lost a Peacock gudgeon for seemingly no reason. I’m thinking it was age.

 

It's possible there was some underlying sickness that wasn't noticeable, or maybe he was stressed from being bullied or something like that... There usually is a reason, just not necessarily a visible one. A month and a half really is a long time though, so I'd assume that it was just a specific fish with a specific reason and the rest will be fine.
I know it's not the same, but I also had a fish die after 2 weeks in the tank with no visible stress, sickness or anything at all... Healthy appetite, getting along with other fish, then suddenly just dead one morning.
Just watch out for other fish deaths, although I don't think there will be any that are related to this one considering parameters are ok and the rest of the fish are ok.

 

I would continue with your normal schedule. Sometimes fish just die for seemingly no reason, I’ve lost a Peacock gudgeon for seemingly no reason. I’m thinking it was age.

It’s really a shame, I thought I was out of the woods because I know rummynose can be pretty wishy washy their first couple of weeks in a new tank.

It's possible there was some underlying sickness that wasn't noticeable, or maybe he was stressed from being bullied or something like that... There usually is a reason, just not necessarily a visible one. A month and a half really is a long time though, so I'd assume that it was just a specific fish with a specific reason and the rest will be fine.
I know it's not the same, but I also had a fish die after 2 weeks in the tank with no visible stress, sickness or anything at all... Healthy appetite, getting along with other fish, then suddenly just dead one morning.
Just watch out for other fish deaths, although I don't think there will be any that are related to this one considering parameters are ok and the rest of the fish are ok.

Thanks for the response! I’ll make sure to keep an eye on everyone else. It’s really just a bummer because everything was going so smoothly.

It is possible.
You time frame would also coincide with new tank not cycled syndrome, or even to many fish added to an existing cycle that couldn't' keep up.
There are other factors like disease or fright from something weird.
Keep an eye on things and keep it clean.

I have a cat that likes to bat at the side of the tank when the kuhlis come out at night. Could this maybe have scared one of the rummynose to death?

 

I have a cat that likes to bat at the side of the tank when the kuhlis come out at night. Could this maybe have scared one of the rummynose to death?

I doubt it. Sometimes Fish really do just die for no reason. It could’ve been genetics, old age (even if you just got it), or underlying health issues.

 

I have a cat that likes to bat at the side of the tank when the kuhlis come out at night. Could this maybe have scared one of the rummynose to death?

I don't know a ton about fish yet, but something similar to this situation is actually a huge problem in bird keeping, especially small, flighty, easily-frightened species like finches, or quail. In finches it's called 'night fright', and what happens is a noise or something wakes them up in the middle of the night, they panic and fly into the bars of their cage hard enough to break their necks. I don't know if that's something that could happen to a fish, but it's a possibility? I've seen how my endlers freak out when you turn the lights on suddenly in the morning, and I could see them ramming into the side of the tank hard enough to hurt themselves, if they derped especially bad. I wouldn't rule it out, personally, I guess?

 

I have a cat that likes to bat at the side of the tank when the kuhlis come out at night. Could this maybe have scared one of the rummynose to death?

When fish get startled from something, especially if they are sleeping, they can go berzerk and bonk themselves into objects or the side of the tank. It's not out of the realm of possibilities. My wife never understood why I get touchy about lights in the room going on or off out of schedule with the tank until she witnessed the aftermath for herself.

 

You asked it there's always an underlying cause. I'd say yes, there's always a underlying cause when anyone or anything dies, but it's not always easily detectable, or preventable. If it was just one fish, and the others aren't showing any symptoms, I wouldn't worry about it too much (other than keeping a close eye on the others for the next week or so).

 

Sadly sometimes we lose fish and never get to the bottom of why it happened.

 

You asked it there's always an underlying cause. I'd say yes, there's always a underlying cause when anyone or anything dies, but it's not always easily detectable, or preventable. If it was just one fish, and the others aren't showing any symptoms, I wouldn't worry about it too much (other than keeping a close eye on the others for the next week or so).

I’ll make sure to closely monitor them. Thank you so much for the response!

When fish get startled from something, especially if they are sleeping, they can go berzerk and bonk themselves into objects or the side of the tank. It's not out of the realm of possibilities. My wife never understood why I get touchy about lights in the room going on or off out of schedule with the tank until she witnessed the aftermath for herself.

That’s very interesting. Last night when I was feeding the kuhlis (30 min after I turn the tank lights off), I accidentally slammed to lid of the tank closed. It’s happened before, but it’s a really loud and sudden noise. Perhaps maybe this?