Mystery of the Missing Fish

[Daxster]

It was a dark and rainy evening, they were lost on a winding road but Bob and Jill thought they saw a light on in the castle at the top of the hill....

Not really, but it could've gone something like that. So about a month ago our yellow guppy disappears out of our 29g tank. We couldn't figure it out. At first we thought he croaked, all the other fish were fine and we couldn't find a trace of him anywhere. We checked in and under all decorations and the pump.

Last week, we added 2 longfin zebra danio to complement the 2 zebra danios we had already. A couple days later I found one of them(the smaller one) floating at the top. I attributed this to the fact that they came from a chain store and stress.

Today, I noticed another danio missing. I checked with my spouse and there were definitely 3 last night. Tonight, I saw that 1 of the 2 remaining danios has a ripped tail fin.

We must have a killer fish among us but I can't figure out which it is.

29 gallon tank running for 1 1/2 yrs
Marineland Biowheel Filter
78 degrees temp
sparsely planted but there is a cave, castle and driftwood that create hiding places

1 1.5" red tail shark
1 1.5" clown pleco
3 1" cardinal tetras
2 1" danio

 

[OrangeCones]

I would suspect the shark.

 

[lauraf]

+1 . . . . . . .

 

[Daxster]

That stinker! I suspected it was some and someone at Petsmart tried to convince me it was my pleco. We just got a bigger tank. I'm hoping that with more space he will calm down.

 

[aakaakaak]

General rule of thumb: If a fish can fit in the mouth of another fish it will try to eat it.

 

[Sageofstupidity]

I thought red tails were semi-aggressive and should not be housed in a peaceful community. Do you think it is just territorial? But I concur with the others, I would put money on the shark unless the pleco is huge.

 

[OrangeCones]

I thought red tails were semi-aggressive and should not be housed in a peaceful community.

I agree. They are better in a semi-aggressive or aggressive tank.

Do you think it is just territorial?

The shark would be territorial of other bottom dwellers, but this is not the case per the OP. It is the smaller shoaling fish that are sleeping at night, when the shark is out hunting, that are disappearing.

 

[OrangeCones]

I'm hoping that with more space he will calm down.

The shark will not 'calm down' in more space. If he was defending a territory against other bottom dwellers, then more space would help. But he will grow 6" or so and get increasing aggressive toward other fish as he grows. He's not compatiable with a peaceful tank.

 

[Daxster]

I'm disappointed to hear that, our lfs store sold him to us a year ago knowing the size and content of our tank.

We were discussing doing cichlids in the 29g tank but I'm not sure when.