Neon tetra disappeared

[IlhamSetiawan]

This is my first time in this forum, I used to have 10 Neon tetras, but today all have disappeared

I also tried 10 Firehead tetra & 10 Silvertip but they disappeared too

Here is my tank inhabitants:

2 Black skirt tetra

2 Denison barb

2 Sunset thicklip gourami

2 Serpae tetra

1 Variatus platy (used to have 3 but 2 of them disappeared)

Some Malaysian trumpet snail

Do anyone know what happened?

Edited August 2, 2023 by IlhamSetiawan

[MattyM]

Did they jump? From what I've read on Denison Barbs they need large groups and a large tank, otherwise they can become aggressive. 

[NOLANANO]

In total you have had 32 fish disappear? No judgment, just making sure I understand the situation. Do they disappear one at a time or you wake up and 10 fish are gone?

Is the background fit to the glass or is it possible for fish to get pinned between the glass and the background? I ask because if you do have a bully in the tank (either Denison Barbs or the Gouramis if I had to guess) then its possible that the smaller fish are going behind the background to hide and then either get stuck or just starve to death. Its also possible they just jumped out but I'd think you would have found a body or 2 if 32 fish jumped out.

Edited August 2, 2023 by NOLANANO

[IlhamSetiawan]

I don't think they jump since my tank has lid, also they disappeared one at a time

[Colu]

I agree with @NOLANANO any chance they got behind your  3-D background and died did you notice any ammonia spikes that would indicate a dead fish in the tank around the time you had fish disappear @IlhamSetiawan

Edited August 3, 2023 by Colu

[Guppysnail]

On 8/2/2023 at 11:05 AM, IlhamSetiawan said:

Some Malaysian trumpet snail

 

On 8/2/2023 at 6:17 PM, IlhamSetiawan said:

they disappeared one at a time

There is a chance they are passing from an unknown illness in the tank. One at a time you probably have more MTS than you know cleaning up the deceased in very short time.  
I would also check behind the 3d background 

[IlhamSetiawan]

On 8/3/2023 at 8:09 AM, Colu said:

any chance they got behind your  3-D background and died

I don't think so because i put white filter floss in background gap

[reefhugger]

 

On 8/3/2023 at 4:33 AM, IlhamSetiawan said:

I don't think so because i put white filter floss in background gap

I'd still check since this is the most likely cause.

[IlhamSetiawan]

On 8/3/2023 at 3:33 PM, IlhamSetiawan said:

On 8/3/2023 at 4:15 PM, reefhugger said:

 

I'd still check since this is the most likely cause.

 

Thats may be, but my suspect is the filter intake, because it has wide gap