Fish dissappearing? (Yoyo loaches or BN plec culprits?)

[JuliaAndFish co.]

Hi, I have noticed recently that some fish have begun to randomly dissappear from my tank. Guppies, a molly, a female betta, and some tetras, and I have deduced that the only thing that could be killing them would be either my 3 yoyo loaches or my female bristlenose pleco. I haven't seen them ever be aggressive towards any other fish, and my tank has plenty hiding spots. I have searched the tank again and again, but I cannot find any sign of bodies or anything . The fish killed were healthy, and all fish are fed enough. My water parameters are:
Ph 6.8
Ammonia 0
Nitrites 0
Nitrates 10
Chlorine 0
If anyone can explain what the problems could be and what to do with it I'd be very grateful

 

[MaloK]

If your loaches are turning on your other fishes. You might want to feed them some more. loll.

What are the size of the fish targeted ?

I seen something like that in the past and it ended being a dragonfly nymph living under the radar.

Depending on the complexity of your decor... They can go unseen forever. they hunt at night and are ruthless facehuggers.

Note that it can take a long time for their eggs to hatch... At their birth they are literal fish food.

But if only "one" makes it's way. They are on another level of hunters.

Both times I encountered these in my tanks is because I used medication in despair of having no clue on what was happening.

And found them dying later in front of the tank.

Here's my latest encounter:

 

[GaryE]

Neither fish is a predator, but they are quickly working scavengers when a fish dies. That probably accounts for the lack of evidence, but not for the causes of death. Something is off.

 

[Fishfunn]

Throwing a question out there, could they get into your filter through the input?

 

[JuliaAndFish co.]

What are the size of the fish targeted ?

They are fully grown guppies, a molly, and a female betta, all approx 1 to 2 inches.
I feel my loaches a lot, I use sinking wafers and flake food.

I seen something like that in the past and it ended being a dragonfly nymph living under the radar

Might be, though I haven't seen any signs and I have moved the hardscape around in search of bodies also...
The fish tend to disappear every couple of days, one guppy yesterday, one molly last Friday...

 

[JuliaAndFish co.]

Throwing a question out there, could they get into your filter through the input?

Nope, no way, it's a Hang on Back, and I have a thing put on the skimmer up top to prevent fish going in, and the bottom has protection also.
I have checked the filter several times as well for any evidence but to no avail

 

[GaryE]

Do you have a cat? That was the solution to a similar mystery when I was a teenager. Just a small slot 2 inches wide at the back of the cover... I caught her because she would leave their eyeballs on the carpet.

 

[Fishfunn]

If any of your fish are dying, the pleco will eat the carcass, but you should see some remains.

 

[MaloK]

From your pictures, it's difficult to say if your tanks have lids.

Could the fish jump out ? And are somewhere behind the tank ?

 

[PygmyPepperJulli]

Neither fish is a predator

Question- I (a noob, this could be totally wrong) have read several horror stories of yoyo loaches eating smaller fish (neon tetras, rasboras, etc). Is this a myth? If so, it would make me feel a lot safer about the future of my tank .

I don't think they'd go for anything as big as a betta though, so this probably isn't it.

Also, how long have they been disappearing? (Over the last few days/weeks/months?)

 

[JuliaAndFish co.]

From your pictures, it's difficult to say if your tanks have lids.

Could the fish jump out ? And are somewhere behind the tank ?

They all have lids, and no slots or anything that they could jump out of.

Do you have a cat? That was the solution to a similar mystery when I was a teenager. Just a small slot 2 inches wide at the back of the cover... I caught her because she would leave their eyeballs on the carpet.

I have 2 but they are not allowed in the house

 

[JuliaAndFish co.]

Also, how long have they been disappearing? (Over the last few days/weeks/months?)

Aproximately 2 months maybe, started around the middle of January

 

[MaloK]

The plot thickens every replies

 

[PygmyPepperJulli]

Are there any caves or pieces of hardscape with a small entrance (so the fish could swim in but maybe not find their way out)? I once lost one of my loaches and turned the tank upside down looking for it (or a corpse)- turns out it was in a tiny hole in one of my logs and wriggled out when I pulled the wood from the water.

Also, could there be anything wrong with the food? (I only think this because if the yoyos and BN only eat sinking pellets etc, the other fish might be affected by another type of food you give them).

How many fish are left in the tank now other than the pleco and yoyos?

 

[JuliaAndFish co.]

So far so good no losses since the guppy. No violence observed between the fish, and all are healthy and eating. I'll keep update if anything happens (let's hope nothing will)