The Planted Tank Forum banner

Why do fish just disappear?

5072 Views 18 Replies 18 Participants Last post by  Italionstallion888
I have a 29 gallon heavily planted aquarium
This is not my first planted aquarium, but it is the first one where a large number of fish have just disappeared over the past 2 years that it has been set up.
Currently I have cherry barbs and neon tetras in the tank and they are doing fine. The barbs are even reproducing in the tank.
But other fish like cory cats, rams, otocinclus, golden wonder killifish, and now Siamese algae eaters just disappear. There are now corpuses’ in the tank no sign of jumping out nothing. They just vanish. One day they are there and then they are gone and not just one at a time over time. I mean the whole lot disappear, like aliens have abducted them.
The only fish that don’t disappear are the cherry barbs and neon tetras. Like I said the barbs are reproducing in the tank. And the water chemistry is excellent. In fact I have taken samples in to be tested to see if I am missing something. They tell me they wish more people came in with water this good.
I’ve talk to my local fish store personnel and they have no answers.
Has anyone else experienced this happening in their tanks?
1 - 19 of 19 Posts
Do you have a lid? Is there any room where you can touch the water? Do you have a cat or dog that may eat jumpers?

That would be my first guess. Second guess maybe their being eaten by tank mates? :icon_conf
Is the 29 gallon possibly a BioCube? If it is the original model, they could have jumped into the back chambers... Happened to me a lot with saltwater.

If you're 100% sure your tank is flawless, perhaps they're getting sick and dying in the plants for some reason, in places you can't find them. Maybe they're getting stuck somewhere, like under driftwood or rock.

Is it possible any of them went nemo-style and swam into the filter, but unlike nemo, failed and got sucked in?

Do you have anything other than fish in the tank? If you have a REALLY good cleanup crew or shrimp or something, it's possible that the fish could be dying from something (illness, injury) and swimming into the plants to die, then they're cleaned up before you can find them.

I had this happen to my first clownfish when I had saltwater. Tore the entire tank apart -- took out every rock, looked in the filter chambers, everything. Never found.

Is there any way something could have gotten spilled in the water to contaminate it? Maybe heavy metals or something? Broken thermometer, heater, ect?
See less See more
i have not so heavily planted 17 gallon tank and yet, my pygmy cories (15 of them) started to disappear one by one. in couple of months there was not a single cory. and it stayed that way for at least 6 months. Then, i took the tank down and while I was pulling all the plants out, I saw one cory. And then another one and another... in the end, I pulled out 12 cories! I put them in my 50 gallon and they immediately disappeared again.
this is not the first time st like that happened. fish can hide unbelievably well :)
Cat's will fish em out if they can get just a paw in the tank,fishes will jump out sometimes if they are able .
Otherwise no,fish just don't dissappear.
Would make sure they ain't all dead somewhere in the tank which would cause sharp spike in ammonia level's.
I vote on the nemo theory. They are in the filter.
Fish that die have incredibly soft bones if they are the smaller types you mention. It is quite easy for them to die and just drift into unseen spots where they are decay and are eaten in natures way. They can also hide very easily. Check any places like hollow wood or holey rocks carefully. It is quite easy to kill some types when I lay rocks out and find them under the pile the next day.
its all in your head, you probably never had them to begin with. :)
Two possibilities: 1. Turned into Scooby Snacks 2. Turned in to plant fertilizer
My small friendly community fish (neons, guppies, kuhlis) can strip a dead neon tetra to a soft spine within a few minutes. The spine then gets dragged off by the Amanos and if I'd never seen it happen I wouldn't ever know what had happened nor believe they can all gobble up a dead fish so quickly.
Is your tank part of the Matrix?
"There is no fish"
Just today I have noticed that my bamboo shrimp (1.5 inches) has disappeared from my 10g planted tank. I last saw him 2 days ago. I had half the plants and stuff out the tank. No sign of him. Not even part of his shell casing. There is no way he got out the tank. So I think the neons and the RCS ate all remnants, even the shell if thats possible. Until I ever find out, MIA presumed KIA.
I was sure that I had lost my vampire shrimp to my cat but then 3 months later I was rearranging some drift wood and there he was living in a small crevice that I couldn't see very easily.

As others have said though, you would be surprised how quickly a dead fish can be consumed in a community tank.
Sounds like you need a high tech surveillance system
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.